docs: add pre-feature cleanup task list and API parity plan

Task list from the 2026-10-08 repo audit, plus the plan for the two
parity fixes found while validating the legacy/ move.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/workflows/build.yaml

@@ -31,11 +31,11 @@ jobs:
             TAG=${{ inputs.tag }}
           fi
           IMAGE=gitea.home.hrajfrisbee.cz/${{ github.repository }}:$TAG
-          docker build -f build/Dockerfile \
+          docker build -f legacy/build/Dockerfile \
             --build-arg GIT_TAG=$TAG \
             --build-arg GIT_COMMIT=${{ github.sha }} \
             --build-arg BUILD_DATE=$(date -u +%Y-%m-%dT%H:%M:%SZ) \
-            -t $IMAGE .
+            -t $IMAGE legacy/
           docker push $IMAGE
 
   build-go:

.gitea/workflows/gitops-update.yaml

@@ -39,10 +39,10 @@ jobs:
       GITEA_TOKEN: ${{ secrets.GITOPS_TOKEN }}
 
     steps:
-      - name: Install git, curl, ca-certificates
+      - name: Install git, curl, ca-certificates, jq
         run: |
           apt-get update -qq
-          apt-get install -y --no-install-recommends git curl ca-certificates
+          apt-get install -y --no-install-recommends git curl ca-certificates jq
 
       - name: Install tea
         run: |
@@ -62,19 +62,29 @@ jobs:
         id: resolve
         run: |
           if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
-            GIT_TAG="${{ inputs.tag }}"
+            IMAGE="gitea.home.hrajfrisbee.cz/${{ github.repository }}:${{ inputs.tag }}-go"
           else
-            # workflow_run: use the ref name of the triggering workflow (the pushed git tag).
+            # workflow_run: head_branch is not populated for tag pushes in Gitea Actions.
-            GIT_TAG="${{ github.event.workflow_run.head_branch }}"
+            # Look up the tag name that points to the triggering commit SHA via the API.
-          fi
+            SHA="${{ github.event.workflow_run.head_sha }}"
+            GIT_TAG=$(curl -fsSL \
+              -H "Authorization: token ${GITEA_TOKEN}" \
+              "https://gitea.home.hrajfrisbee.cz/api/v1/repos/${{ github.repository }}/tags?limit=50" \
+              | jq -r --arg sha "$SHA" '.[] | select(.commit.sha == $sha) | .name')
             IMAGE="gitea.home.hrajfrisbee.cz/${{ github.repository }}:${GIT_TAG}-go"
+          fi
           echo "image=${IMAGE}" >> "$GITHUB_OUTPUT"
           echo "Resolved image: ${IMAGE}"
 
-      - name: Configure git identity
+      - name: Configure git identity and credentials
         run: |
           git config --global user.name  "uh-cli bot"
           git config --global user.email "bot@hrajfrisbee.cz"
+          # Store credentials separately so the --git-repo URL stays clean.
+          # Tea matches the login URL against the remote URL; embedded credentials
+          # break that matching and cause "path segment [0] is empty" on pr create.
+          git config --global credential.helper store
+          echo "https://kacerr:${GITEA_TOKEN}@gitea.home.hrajfrisbee.cz" >> ~/.git-credentials
 
       - name: Authenticate tea
         run: |
@@ -85,10 +95,11 @@ jobs:
 
       - name: Open image-update PR (or dry run)
         run: |
+          set -x
           uh-cli -v gitops deployment update \
             --deployment-name fuj-management \
             --deployment-namespace fuj \
             --set-image "${{ steps.resolve.outputs.image }}" \
-            --git-repo "https://kacerr:${GITEA_TOKEN}@gitea.home.hrajfrisbee.cz/kacerr/home-kubernetes" \
+            --git-repo "https://gitea.home.hrajfrisbee.cz/kacerr/home-kubernetes" \
             --git-path gitops/home-kubernetes \
             ${{ (github.event_name == 'workflow_dispatch' && inputs.dry_run == 'true') && '--dry-run' || '' }}

.vscode/launch.json

@@ -2,14 +2,16 @@
     "version": "0.2.0",
     "configurations": [
         {
-            "name": "Python Debugger: Flask",
+            "name": "Python Debugger: Flask (legacy)",
             "type": "debugpy",
             "request": "launch",
             "module": "flask",
-            "python": "${workspaceFolder}/.venv/bin/python",
+            "python": "${workspaceFolder}/legacy/.venv/bin/python",
+            "cwd": "${workspaceFolder}/legacy",
             "env": {
                 "FLASK_APP": "app.py",
-                "FLASK_DEBUG": "1"
+                "FLASK_DEBUG": "1",
+                "CREDENTIALS_PATH": "${workspaceFolder}/.secret/fuj-management-bot-credentials.json"
             },
             "args": [
                 "run",

CHANGELOG.md

@@ -1,5 +1,30 @@
 # Changelog
 
+## 2026-10-08 11:34 CEST — fix(python): return months_to_show from /api/adults and /api/juniors
+
+- Go already returned `months_to_show` in the JSON API; Python only passed it to its HTML templates. Backported the key so the API contract matches and `make parity` reports 3/3 routes.
+- Key files: `legacy/app.py`, `legacy/tests/test_app.py`.
+
+## 2026-10-08 11:34 CEST — fix: VS is always a string, on read and on write
+
+- Go rendered numeric sheet cells with `fmt.Sprint`, so a numeric VS came out as `2.609767878e+09`. Text columns of the payments sheet now go through `sheets.CellString` (plain digits); bank inference uses it too.
+- Both sync implementations now append VS as a text cell (leading apostrophe under `USER_ENTERED`), so Sheets no longer stores it as a number or drops leading zeros. Existing rows are unchanged.
+- Key files: `go/internal/io/sheets/cell.go`, `go/internal/services/membership/sources.go`, `go/internal/services/banksync/{sync,infer}.go`, `legacy/scripts/sync_fio_to_sheets.py`.
+
+## 2026-10-08 11:33 CEST — refactor: move Python implementation to legacy/, Go is primary
+
+- Go (`go/`) is now the primary implementation. The original Python version moved to `legacy/` (`app.py`, `scripts/`, `templates/`, `tests/`, `pyproject.toml`, `uv.lock`, `build/`) and is considered legacy; new features are still built in both.
+- `CLAUDE.md` rewritten for the Go-first layout, with a "Dual implementation rule" section.
+- Makefile Python targets keep their names and point at `legacy/`; virtualenv is `legacy/.venv`, Python cache is `legacy/tmp/`; `CREDENTIALS_PATH` is exported pointing at the root `.secret/` file.
+- CI builds the Python image with `legacy/` as context; the image no longer contains the Makefile. `legacy/.dockerignore` now takes effect and excludes nested `__pycache__`.
+- Go comments, fixture README, capture script and VS Code launch config updated to the new paths.
+
+## 2026-06-12 19:32 CEST — feat(ci): gitops image-update PR workflow
+
+- Added `.gitea/workflows/gitops-update.yaml`: after each successful Go image build, `uh-cli gitops deployment update` opens a PR in `kacerr/home-kubernetes` bumping the `fuj-management` Deployment (namespace `fuj`) to the new image tag.
+- Supports `workflow_run` auto-trigger and `workflow_dispatch` with `dry_run` / `uh_cli_version` inputs.
+- Requires `GITOPS_TOKEN` repo secret (Gitea PAT with write+PR access to `home-kubernetes`).
+
 ## 2026-05-24 21:58 CEST — feat(fees): update adult monthly rates for 2026-05 through 2026-08
 
 - 2026-05: 700 → 450 CZK; 2026-06/07/08: 600 CZK (new months added).

CLAUDE.md

@@ -4,28 +4,62 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 ## Project Status
 
-Flask-based financial management system for FUJ (Frisbee Ultimate Jablonec). Handles attendance-based fee calculation, Fio bank transaction sync, payment reconciliation, and a web dashboard.
+Financial management system for FUJ (Frisbee Ultimate Jablonec). Handles attendance-based fee calculation, Fio bank transaction sync, payment reconciliation, and a web dashboard.
+
+- **Go is the primary implementation** (`go/`). It is the version that is built, deployed and developed first.
+- **Python is legacy** (`legacy/`). The project was originally developed in Python (Flask); that version is kept runnable and in sync, but is considered legacy from now on.
+
+## Dual implementation rule
+
+Until the Python version is retired, **every new feature and every behaviour change must be implemented in both Go and Python**:
+
+1. Implement and test in Go first (`go/`).
+2. Mirror the change in the legacy Python code (`legacy/`), including its tests.
+3. Keep the two in parity: shared constants (fee rates, merged months, bank accounts, sheet IDs) must match on both sides, and the JSON API contract (`/api/adults`, `/api/juniors`, `/api/payments`) must stay identical. The HTML frontends are allowed to diverge.
+4. If a pure function's behaviour changes, add or update seeds in `legacy/scripts/_fixture_seeds.py`, run `make capture-fixtures`, and make sure `make go-test-all` passes. With both servers running, `make parity` diffs the live JSON APIs.
+
+Go-only or Python-only changes are fine for things that exist on one side only (build, tooling, HTML/CSS/JS, refactors with no behaviour change).
 
 ## Key Constraints
 
 - **PII separation**: Member data (names, emails, payment info) must never be committed to git. Enforce config/data separation from day one.
-- **Configuration**: External service IDs, credentials, and tunable parameters are centralized in `scripts/config.py`. Domain-specific constants (fees, merged months) stay in their respective modules.
+- **Configuration**: External service IDs, credentials, and tunable parameters are centralized in `go/internal/config/config.go` (mirrored in `legacy/scripts/config.py`). Domain-specific constants (fees, merged months) stay in their respective modules.
 
 ## Development Setup
 
-This project uses `uv` for dependency management.
+Go (primary): a recent Go toolchain (see `go/go.mod`) and `golangci-lint`.
 
 ```bash
-uv venv && uv sync
+make go-build     # builds bin/fuj
-source .venv/bin/activate
 ```
 
-Set `PYTHONPATH=scripts:.` when running scripts directly (the Makefile does this automatically).
+Python (legacy) uses `uv`; the project file and virtualenv live in `legacy/`.
+
+```bash
+make venv         # uv sync --project legacy  →  legacy/.venv
+```
+
+The Makefile sets `PYTHONPATH` (`legacy/scripts:legacy`) and `CREDENTIALS_PATH` (`.secret/fuj-management-bot-credentials.json` at the repo root) for the Python targets. Set both yourself when running Python scripts directly.
 
 ## Commands
 
+Go (primary):
+
 ```bash
-make web          # Start dashboard at http://localhost:5001
+make web-go         # Build and start dashboard at http://localhost:8080
+make go-build       # Build bin/fuj
+make go-test        # Unit tests (go test -race ./...)
+make go-parity      # Parity tests against the captured Python fixtures
+make go-test-all    # Both of the above
+make go-lint        # golangci-lint
+make go-run ARGS="fees"        # Run a subcommand: server, fees, reconcile, sync, infer, version
+make go-sync-debug [DAYS=N]    # Dry-run bank sync with debug logs
+```
+
+Python (legacy):
+
+```bash
+make web-py       # Start dashboard at http://localhost:5001 (make web is an alias)
 make web-debug    # Same with FLASK_DEBUG=1
 make test         # Run all tests (unittest discover)
 make test-v       # Tests with verbose output
@@ -33,12 +67,20 @@ make fees         # Print fee report from attendance sheet
 make sync-2026    # Sync Fio bank transactions for 2026 to Google Sheets
 make infer        # Auto-fill Person/Purpose/Amount columns in payments sheet
 make reconcile    # Print balance report from Google Sheets data
-make image        # Build Docker image
+make image        # Build the legacy Python Docker image
+```
+
+Cross-implementation:
+
+```bash
+make capture-fixtures   # Regenerate go/tests/fixtures from the Python implementation
+make parity             # Diff /api/* between web-py (:5001) and web-go (:8080); both must be running
 ```
 
 Run a single test:
 ```bash
-PYTHONPATH=scripts:. python -m unittest tests.test_app.TestWebApp.test_adults_route
+cd go && go test ./internal/domain/reconcile -run TestName
+cd legacy && PYTHONPATH=scripts:. .venv/bin/python -m unittest tests.test_app.TestWebApp.test_adults_route
 ```
 
 ## Architecture
@@ -46,25 +88,45 @@ PYTHONPATH=scripts:. python -m unittest tests.test_app.TestWebApp.test_adults_ro
 ### Data flow
 
 ```
-Google Sheets (attendance) ──► attendance.py ──► reconcile() ──► Flask routes ──► templates/
+Google Sheets (attendance) ──► attendance loader ──► reconcile ──► HTTP handlers ──► templates
-Google Sheets (payments)   ──► match_payments.py ──┘
+Google Sheets (payments)   ──► payments loader   ──┘
-Fio Bank API               ──► sync_fio_to_sheets.py ──► Google Sheets (payments)
+Fio Bank API               ──► bank sync ──► Google Sheets (payments)
 ```
 
-### Key modules
+### Repository layout
 
-- `app.py` — Flask app; routes for `/adults`, `/juniors`, `/payments`, `/sync-bank`, `/qr`, `/flush-cache`
+- `go/` — primary implementation (single binary `fuj`, templates and static assets embedded).
-- `scripts/attendance.py` — Fetches attendance CSV from Google Sheets, computes per-member per-month fees. Contains fee rate constants (`ADULT_FEE_DEFAULT`, `JUNIOR_FEE_DEFAULT`) and `ADULT_MERGED_MONTHS` / `JUNIOR_MERGED_MONTHS` dicts.
+- `legacy/` — legacy Python implementation (`app.py`, `scripts/`, `templates/`, `tests/`, `pyproject.toml`, `build/Dockerfile`).
-- `scripts/match_payments.py` — `reconcile()` matches transactions to members/months. `fetch_sheet_data()` reads the payments sheet. `fetch_exceptions()` reads the `exceptions` tab.
+- `docs/` — documentation; `docs/plans/` holds plans and task lists.
-- `scripts/cache_utils.py` — Invalidation via Google Drive API `modifiedTime`; falls back to 5-minute TTL buckets when Drive API is unavailable. Cache files live in `tmp/`.
+- `.gitea/workflows/` — CI: image builds on tag push, gitops image-update PR.
-- `scripts/sync_fio_to_sheets.py` — Pulls Fio bank transactions and appends them to the payments Google Sheet.
+
-- `scripts/infer_payments.py` — Fills in Person/Purpose/Inferred Amount columns using name-matching heuristics.
+### Key modules — Go (primary)
-- `scripts/config.py` — All external IDs, paths, and tunable TTLs. Override via env vars (`CREDENTIALS_PATH`, `BANK_ACCOUNT`, `CACHE_TTL_SECONDS`).
+
+- `go/cmd/fuj` — CLI entry point; subcommands `server`, `fees`, `reconcile`, `sync`, `infer`, `version`.
+- `go/cmd/parity` — diffs the JSON API of the Go and Python servers.
+- `go/internal/config` — sheet IDs, bank accounts, env-driven settings (`CREDENTIALS_PATH`, `CACHE_DIR`, `CACHE_TTL_SECONDS`, `CACHE_API_CHECK_TTL_SECONDS`, `MONTHS_TO_SHOW`, `SERVER_ADDR`, `LOG_LEVEL`, `FIO_API_TOKEN_NEW` / `FIO_API_TOKEN_OLD`).
+- `go/internal/domain` — pure logic: `fees` (rates, `CalculateFee`, `CalculateJuniorFee`), `reconcile`, `matching` (name matching, inference), `czech` (normalize, month parsing), `money`, `synch` (sync IDs).
+- `go/internal/io` — external systems: `attendance` (CSV export), `sheets`, `drive`, `fio` (API + transparent-page scraper), `cache` (file cache). Each has a fake for tests.
+- `go/internal/services` — `membership` (loading, merged months, fee and reconcile reports) and `banksync` (Fio sync + inference).
+- `go/internal/web` — routes for `/adults`, `/juniors`, `/payments`, `/sync-bank`, `/flush-cache`, `/qr`, `/version`, `/api/*`; `templates/` and `static/` are embedded.
+- `go/tests` — parity tests and the scrubbed fixture corpus captured from Python.
+
+### Key modules — Python (legacy)
+
+- `legacy/app.py` — Flask app; routes for `/adults`, `/juniors`, `/payments`, `/sync-bank`, `/qr`, `/flush-cache`, `/api/*`
+- `legacy/scripts/attendance.py` — Fetches attendance CSV from Google Sheets, computes per-member per-month fees. Contains fee rate constants (`ADULT_FEE_DEFAULT`, `JUNIOR_FEE_DEFAULT`) and `ADULT_MERGED_MONTHS` / `JUNIOR_MERGED_MONTHS` dicts.
+- `legacy/scripts/match_payments.py` — `reconcile()` matches transactions to members/months. `fetch_sheet_data()` reads the payments sheet. `fetch_exceptions()` reads the `exceptions` tab.
+- `legacy/scripts/cache_utils.py` — Invalidation via Google Drive API `modifiedTime`; falls back to 5-minute TTL buckets when Drive API is unavailable. Cache files live in `legacy/tmp/`.
+- `legacy/scripts/sync_fio_to_sheets.py` — Pulls Fio bank transactions and appends them to the payments Google Sheet.
+- `legacy/scripts/infer_payments.py` — Fills in Person/Purpose/Inferred Amount columns using name-matching heuristics.
+- `legacy/scripts/views.py` — View models shared by the HTML routes and the JSON API.
+- `legacy/scripts/config.py` — All external IDs, paths, and tunable TTLs. Override via env vars (`CREDENTIALS_PATH`, `CACHE_TTL_SECONDS`, `MONTHS_TO_SHOW`).
+- `legacy/scripts/capture_fixtures.py`, `scrub_fixtures.py`, `_fixture_seeds.py` — produce the scrubbed parity fixtures for Go.
 
 ### Member tiers
 
 Tiers are set in column B of the attendance sheet:
-- `A` — Adult, pays fees (per-month rate from `ADULT_FEE_MONTHLY_RATE`, fallback 700 CZK for 2+ sessions; 200 CZK for exactly 1)
+- `A` — Adult, pays fees (per-month rate from `AdultFeeMonthlyRate` / `ADULT_FEE_MONTHLY_RATE`, fallback 700 CZK for 2+ sessions; 200 CZK for exactly 1)
 - `J` — Junior attending adult practices; their attendance is merged with the junior sheet
 - `X` — Excluded from junior fee calculation (coaches, etc.)
 
@@ -76,17 +138,17 @@ Tiers are set in column B of the attendance sheet:
 
 ### Merged months
 
-`ADULT_MERGED_MONTHS` / `JUNIOR_MERGED_MONTHS` in `attendance.py` map a source month to a target month (e.g., `"2025-12": "2026-01"` merges December into January billing). The target month accumulates attendance from both months.
+`AdultMergedMonths` / `JuniorMergedMonths` in `go/internal/services/membership/sources.go` (`ADULT_MERGED_MONTHS` / `JUNIOR_MERGED_MONTHS` in `legacy/scripts/attendance.py`) map a source month to a target month (e.g., `"2025-12": "2026-01"` merges December into January billing). The target month accumulates attendance from both months.
 
 ### Caching
 
-`get_cached_data()` in `app.py` checks the Drive API `modifiedTime` before each request and serves a JSON file from `tmp/` when the sheet hasn't changed. Cache is warmed up at startup (`warmup_cache()`). Flush via `/flush-cache` (POST) or `flush_cache()`.
+Both implementations check the Drive API `modifiedTime` and serve a cached JSON file when the sheet hasn't changed, falling back to 5-minute TTL buckets when the Drive API is unavailable. Go: `go/internal/io/cache`, files in `tmp/go/` (`CACHE_DIR`). Python: `get_cached_data()` in `legacy/app.py`, files in `legacy/tmp/`, warmed up at startup (`warmup_cache()`). Flush via `/flush-cache` (POST).
 
 ### Payments sheet columns
 
 `Date | Amount | manual fix | Person | Purpose | Inferred Amount | Sender | VS | Message | Bank ID | Sync ID`
 
-`Person` and `Purpose` are written by `infer_payments.py` and can be manually corrected. `manual fix` column presence disables re-inference for that row. Multiple people or months are comma-separated in Person/Purpose.
+`Person` and `Purpose` are written by the inference step (`fuj infer` / `infer_payments.py`) and can be manually corrected. `manual fix` column presence disables re-inference for that row. Multiple people or months are comma-separated in Person/Purpose.
 
 ### QR codes
 

Makefile

@@ -1,26 +1,30 @@
 .PHONY: help fees match web web-py web-debug web-go go-build go-test go-test-all go-parity go-run go-sync-debug go-lint capture-fixtures parity image run sync sync-2026 test test-v docs
 
-export PYTHONPATH := scripts:$(PYTHONPATH)
+# Legacy Python implementation lives in legacy/ (Go in go/ is primary).
-VENV := .venv
+LEGACY := legacy
-PYTHON := $(VENV)/bin/python3
+export PYTHONPATH := $(CURDIR)/$(LEGACY)/scripts:$(CURDIR)/$(LEGACY):$(PYTHONPATH)
-CREDENTIALS := .secret/fuj-management-bot-credentials.json
+VENV := $(LEGACY)/.venv
+PYTHON := $(CURDIR)/$(VENV)/bin/python3
+CREDENTIALS := $(CURDIR)/.secret/fuj-management-bot-credentials.json
+# Both implementations read CREDENTIALS_PATH; the Python default would resolve under legacy/.
+export CREDENTIALS_PATH ?= $(CREDENTIALS)
 
 GO_SRC := go
 GO_BIN := bin/fuj
 
-$(PYTHON): .venv/.last_sync
+$(PYTHON): $(VENV)/.last_sync
 
-.venv/.last_sync: pyproject.toml
+$(VENV)/.last_sync: $(LEGACY)/pyproject.toml
-	uv sync
+	uv sync --project $(LEGACY)
-	touch .venv/.last_sync
+	touch $(VENV)/.last_sync
 
 help:
 	@echo "Available targets:"
 	@echo "  make fees        - Calculate monthly fees from the attendance sheet"
 	@echo "  make match       - Match Fio bank payments against expected attendance fees"
-	@echo "  make web         - Start Python dashboard (alias for web-py, until M8)"
+	@echo "  make web         - Start legacy Python dashboard (alias for web-py)"
-	@echo "  make web-py      - Start Python dashboard on :5001"
+	@echo "  make web-py      - Start legacy Python dashboard on :5001"
-	@echo "  make web-go      - Build and start Go dashboard on :8080"
+	@echo "  make web-go      - Build and start Go dashboard on :8080 (primary)"
 	@echo "  make web-debug   - Start Python dashboard in debug mode"
 	@echo "  make go-build    - Build Go binary to bin/fuj"
 	@echo "  make go-test     - Run Go unit tests"
@@ -44,21 +48,21 @@ help:
 	@echo "  make docs        - Serve documentation in a browser"
 
 venv:
-	uv sync
+	uv sync --project $(LEGACY)
 
 fees: $(PYTHON)
-	$(PYTHON) scripts/calculate_fees.py
+	$(PYTHON) $(LEGACY)/scripts/calculate_fees.py
 
 match: $(PYTHON)
-	$(PYTHON) scripts/match_payments.py
+	$(PYTHON) $(LEGACY)/scripts/match_payments.py
 
 web: web-py
 
 web-py: $(PYTHON)
-	$(PYTHON) app.py
+	$(PYTHON) $(LEGACY)/app.py
 
 web-debug: $(PYTHON)
-	FLASK_DEBUG=1 $(PYTHON) app.py
+	FLASK_DEBUG=1 $(PYTHON) $(LEGACY)/app.py
 
 go-build:
 	cd $(GO_SRC) && go build -trimpath \
@@ -82,10 +86,10 @@ capture-fixtures: $(PYTHON)
 	              infer_transaction_details format_date reconcile; do \
 	    dir="go/tests/fixtures/$$([[ $$func == reconcile ]] && echo reconcile || echo pure/$$func)"; \
 	    mkdir -p "$$dir"; \
-	    PYTHONPATH=scripts:. $(PYTHON) scripts/capture_fixtures.py --func $$func --all \
+	    $(PYTHON) $(LEGACY)/scripts/capture_fixtures.py --func $$func --all \
 	    | while IFS= read -r line; do \
 	        case_id=$$(echo "$$line" | $(PYTHON) -c "import sys,json; print(json.load(sys.stdin)['case'])"); \
-	        echo "$$line" | $(PYTHON) scripts/scrub_fixtures.py > "$$dir/$${case_id}.json"; \
+	        echo "$$line" | $(PYTHON) $(LEGACY)/scripts/scrub_fixtures.py > "$$dir/$${case_id}.json"; \
 	    done; \
 	    echo "  $$func done"; \
 	done
@@ -112,34 +116,34 @@ image:
 		--build-arg GIT_TAG=$$(git describe --tags --always 2>/dev/null || echo "untagged") \
 		--build-arg GIT_COMMIT=$$(git rev-parse --short HEAD) \
 		--build-arg BUILD_DATE=$$(date -u +%Y-%m-%dT%H:%M:%SZ) \
-		-f build/Dockerfile .
+		-f $(LEGACY)/build/Dockerfile $(LEGACY)
 
 run:
 	docker run -it --rm -p 5001:5001 -v $(CURDIR)/.secret:/app/.secret:ro fuj-management:latest
 
 sync: $(PYTHON)
-	$(PYTHON) scripts/sync_fio_to_sheets.py --credentials .secret/fuj-management-bot-credentials.json
+	$(PYTHON) $(LEGACY)/scripts/sync_fio_to_sheets.py --credentials $(CREDENTIALS)
 
 sync-2025: $(PYTHON)
-	$(PYTHON) scripts/sync_fio_to_sheets.py --credentials .secret/fuj-management-bot-credentials.json --from 2025-10-01 --to 2025-12-31 --sort-by-date
+	$(PYTHON) $(LEGACY)/scripts/sync_fio_to_sheets.py --credentials $(CREDENTIALS) --from 2025-10-01 --to 2025-12-31 --sort-by-date
 
 sync-2026: $(PYTHON)
-	$(PYTHON) scripts/sync_fio_to_sheets.py --credentials .secret/fuj-management-bot-credentials.json --from 2026-01-01 --to 2026-12-31 --sort-by-date
+	$(PYTHON) $(LEGACY)/scripts/sync_fio_to_sheets.py --credentials $(CREDENTIALS) --from 2026-01-01 --to 2026-12-31 --sort-by-date
 
 sync-debug: $(PYTHON)  ## Dry-run Python sync with Fio diagnostics and txn table (default DAYS=30)
-	$(PYTHON) scripts/sync_fio_to_sheets.py --credentials .secret/fuj-management-bot-credentials.json --days $(DAYS) --dry-run --print-fio-table
+	$(PYTHON) $(LEGACY)/scripts/sync_fio_to_sheets.py --credentials $(CREDENTIALS) --days $(DAYS) --dry-run --print-fio-table
 
 infer: $(PYTHON)
-	$(PYTHON) scripts/infer_payments.py --credentials $(CREDENTIALS)
+	$(PYTHON) $(LEGACY)/scripts/infer_payments.py --credentials $(CREDENTIALS)
 
-reconcile:  ## Match payments against attendance
+reconcile: $(PYTHON) ## Match payments against attendance
-	export PYTHONPATH=$(PYTHONPATH):$(CURDIR)/scripts && $(PYTHON) scripts/match_payments.py --credentials $(CREDENTIALS)
+	$(PYTHON) $(LEGACY)/scripts/match_payments.py --credentials $(CREDENTIALS)
 
 test: $(PYTHON) ## Run web application tests
-	export PYTHONPATH=$(PYTHONPATH):$(CURDIR)/scripts:$(CURDIR) && $(PYTHON) -m unittest discover tests
+	cd $(LEGACY) && $(PYTHON) -m unittest discover tests
 
 test-v: $(PYTHON) ## Run tests with verbose output
-	export PYTHONPATH=$(PYTHONPATH):$(CURDIR)/scripts:$(CURDIR) && $(PYTHON) -m unittest discover -v tests
+	cd $(LEGACY) && $(PYTHON) -m unittest discover -v tests
 
 docs: ## Serve documentation locally
 	@echo "Starting documentation server at http://localhost:8000"

docs/README.md

@@ -4,6 +4,8 @@ Welcome to the documentation for the FUJ Management application.
 
 This project automates financial and operational management for the FUJ (Frisbee Ultimate Jablonec) club.
 
+> **Go is the primary implementation** (`go/`). The project was originally developed in Python; that version now lives in `legacy/` and is considered legacy. New features are still built in both. Most guides below predate this change and describe the Python version with its old paths (`app.py`, `scripts/` are now `legacy/app.py`, `legacy/scripts/`).
+
 ## Navigation
 
 Use the sidebar to explore the documentation:

docs/plans/2026-10-08-1026-pre-feature-cleanup-tasks.md

@@ -0,0 +1,157 @@
+# Pre-feature cleanup — task list
+
+Findings from a full repo audit on 2026-10-08, written up as tasks to clear
+before new feature work starts. Companion to the Go rewrite tracker,
+[2026-05-03-2349-go-backend-rewrite-progress.md](2026-05-03-2349-go-backend-rewrite-progress.md).
+
+## State at audit time
+
+- Two full implementations live side by side: Flask (`app.py`, `scripts/`,
+  `templates/`) and Go (`go/`). Recent changes were made in both.
+- Update 2026-10-08: the Python code was moved to `legacy/` after this audit.
+  Python paths below are relative to `legacy/` (`build/Dockerfile` is now
+  `legacy/build/Dockerfile`).
+- Python tests pass (32 tests). Go unit tests and the parity suite pass.
+  Go lint could not run (see T7).
+- The gitops workflow bumps the cluster deployment to the `-go` image, so Go
+  appears to be what is deployed. This was not verified against the cluster.
+- `CLAUDE.md` and all docs outside `docs/plans/` describe a Python-only
+  project. The rewrite tracker stops at M6; M7 and M8 are untouched.
+
+## How to use
+
+- Tick a checkbox when the task's PR or commit lands and append the SHA.
+- Tasks in "Fix first" are small and independent of each other and of the
+  cutover decision. Do them in any order.
+- T5 is a decision. Several cleanup tasks become unnecessary once it is made;
+  they are marked "moot if Python is retired".
+
+---
+
+## Fix first
+
+- [ ] **T1** Remove the secret leak in `.gitea/workflows/kubernetes-deploy.yaml`.
+  - It runs on every push to every branch and deploys nothing.
+  - It echoes the raw Vault login response, the Kanidm token response and the
+    OIDC token response body to the log, and dumps the environment twice.
+  - It uses `--insecure-skip-tls-verify=true`.
+  - Delete or disable the workflow. Rotate the Vault AppRole secret and the
+    Kanidm API token if anyone else can read the CI logs.
+- [ ] **T2** Confirm the fee rates for 2026-09 onward.
+  - `ADULT_FEE_MONTHLY_RATE` ends at 2026-08 in `scripts/attendance.py` and
+    `go/internal/domain/fees/fees.go`.
+  - September and October 2026 are billed at the defaults: 700 CZK adults,
+    500 CZK juniors.
+  - If those are not the intended rates, add the months in both files.
+- [ ] **T3** Remove the hardcoded 2026 window from Python `/sync-bank`
+  (`app.py`, the `sync_to_sheets` call with `2026-01-01` / `2026-12-31`).
+  - It stops picking up transactions on 2027-01-01. Go already uses the
+    current year.
+  - Same applies to the `sync-2026` Makefile target.
+  - Moot if Python is retired before then.
+- [ ] **T4** Remove member names from tracked files (PII rule in `CLAUDE.md`).
+  - `CHANGELOG.md` line 29 names a member in a fix description.
+  - `tests/test_match_payments.py`, `tests/test_reconcile_exceptions.py` and
+    `go/internal/domain/reconcile/reconcile_test.go` use names that may be
+    real. Check them and replace with obviously fictional ones.
+  - Three files in `docs/plans/` contain the same names:
+    `2026-05-05-1717-payment-person-name-canonicalization.md`,
+    `2026-05-06-1626-infer-payments-junior-roster.md`,
+    `2026-05-11-2353-fill-first-multi-month-allocation.md`.
+  - The parity fixtures under `go/tests/fixtures/` are scrubbed and need no
+    change.
+  - Decide whether the names also need removing from git history.
+
+## Decide before new features
+
+- [ ] **T5** Decide how to finish the Python → Go cutover (M7 and M8 in the
+  rewrite tracker).
+  - Recommended: declare Go primary now, freeze Python, run one month-end
+    comparison of the balance report on both sides, then delete Python.
+  - Until this is done, every feature has to be written twice.
+  - Confirm first that the cluster really runs the `-go` image.
+- [ ] **T6** Add a test job to CI.
+  - `.gitea/workflows/build.yaml` only builds images on tag push. Nothing
+    runs tests.
+  - Run `go test -race ./...`, the parity suite (`-tags=parity`) and
+    `golangci-lint` on pull requests.
+  - Stop building the Python image on every tag once Python is retired.
+- [ ] **T7** Fix `make go-lint`.
+  - `go/.golangci.yml` is in the v1 config format. golangci-lint 2.12 refuses
+    to load it ("unsupported version of the configuration").
+  - Migrate the config to v2 and pin the linter version used in CI.
+- [ ] **T8** Protect the side-effectful routes.
+  - Neither app has any authentication.
+  - `GET /sync-bank` writes to the payments sheet, so a link prefetcher or
+    crawler can trigger a sync. Change it to POST with a confirmation page,
+    as `/flush-cache` already does.
+  - Confirm that the ingress enforces access control, or add it in the app.
+  - The Go server uses `http.ListenAndServe` with no read, write or idle
+    timeouts (`go/internal/web/server.go`). Use an `http.Server` with
+    timeouts.
+- [ ] **T9** Move fee rates and merged months out of code.
+  - Today a rate change needs a code change in two languages and a release.
+  - Candidate: a tab in the payments sheet, read the same way as
+    `exceptions`.
+  - This also removes the cause of T2.
+
+## Cleanup
+
+- [x] **T10** Rewrite `CLAUDE.md` for the current state: Go commands,
+  architecture and key modules, and which backend is primary. Done with the
+  move of Python to `legacy/`.
+- [ ] **T11** Collapse the documentation into one set.
+  - `docs/by-claude-opus/`, `docs/by-gemini/` and the top-level docs overlap,
+    date from February–March 2026 and predate the Go rewrite.
+  - Update `docs/_sidebar.md` and `docs/README.md` to match.
+- [ ] **T12** Update the rewrite tracker.
+  - M6.7 is unchecked although the changelog records it as done.
+  - M7.1 and M8.4 refer to a `docker-compose.yml` that does not exist.
+- [ ] **T13** Remove leftovers: `.agent/rules.md` (Antigravity config) and
+  `prompts/`.
+- [ ] **T14** Prune merged branches: 42 local and 44 remote branches are
+  fully merged into `main`.
+- [ ] **T15** Clean up `.claude/settings.json`.
+  - It is tracked and contains absolute paths under one user's home
+    directory and one-off commands.
+  - Keep only shared, generic permissions there; move the rest to
+    `.claude/settings.local.json`, which is already ignored.
+- [ ] **T16** Align versions.
+  - `pyproject.toml` says `0.10`; git tags are at `0.39`.
+  - `build/Dockerfile` pip-installs unpinned packages and ignores `uv.lock`.
+  - `go.mod` and `go/build/Dockerfile` are on Go 1.26; the local toolchain is
+    1.27.
+  - Dependencies on both sides are a few months behind.
+  - The Python items are moot if Python is retired.
+- [ ] **T17** Stop the Python tests from calling live Google APIs.
+  - `warmup_cache()` runs at import of `app.py`, so `make test` makes real
+    Drive and Sheets read calls and needs the credentials file.
+  - Moot if Python is retired.
+- [ ] **T18** Set the time zone in the Go container.
+  - The image has no time zone configured, so `time.Now()` is UTC and the
+    "current month" flips one to two hours late at month boundaries.
+  - The Python image sets `Europe/Prague`.
+- [ ] **T19** Decide where `fujarna/` lives.
+  - `fujarna/project.md` is untracked. It is a brief for a separate
+    tournament website and shares almost nothing with this codebase.
+  - Options: its own repository, or a clearly separate Go module here.
+- [ ] **T20** Add tests for the untested Go packages: `cmd/fuj`,
+  `internal/io/sheets`, `internal/io/drive`, `internal/config` (about 590
+  lines in total).
+
+## Found during validation of the `legacy/` move
+
+Plan: [2026-10-08-1103-api-parity-vs-months-to-show.md](2026-10-08-1103-api-parity-vs-months-to-show.md).
+
+- [x] **T21** Go rendered numeric VS cells in exponent form
+  (`2.609767878e+09`). Sheet text cells now go through `sheets.CellString`.
+- [x] **T22** Python `/api/adults` and `/api/juniors` did not return
+  `months_to_show`. Backported; `make parity` reports 3/3 routes matching.
+- [x] **T23** Write VS to the payments sheet as text. Both sync
+  implementations use `USER_ENTERED`, so Sheets stored VS as a number and
+  dropped leading zeros. New rows now carry a text marker; existing rows are
+  left as they are and are read correctly either way.
+
+## Notes & decisions
+
+(Add entries as you go. Format: `YYYY-MM-DD — short note`.)

docs/plans/2026-10-08-1103-api-parity-vs-months-to-show.md

@@ -0,0 +1,112 @@
+# Fix the two Go/Python parity differences
+
+## Context
+
+Running `make parity` against both containers on 2026-10-08 reported
+`0/3 routes match`. Two causes, neither related to the move to `legacy/`:
+
+1. **VS rendered in scientific notation by Go.** The payments sheet is read
+   with `UNFORMATTED_VALUE`, so a numeric VS cell arrives as `float64`. Go
+   stringifies cells with `fmt.Sprint`, which prints any float ≥ 1e6 in
+   exponent form (`2.609767878e+09`). Python already converts integer floats
+   to plain digits for VS (`get_str` in `fetch_sheet_data`). VS must always be
+   a plain string.
+2. **`months_to_show` missing from the Python JSON API.** Go returns it in
+   `/api/adults` and `/api/juniors` (and it is `required` in the committed
+   schemas). Python already has the feature in its HTML pages
+   (`MONTHS_TO_SHOW` is passed to the templates) but never added the key to
+   the API responses. Backport the key so the API contract matches.
+
+Outcome: `make parity` reports 3/3 routes matching.
+
+## Branching
+
+Both are bug fixes that touch `legacy/` paths, so they depend on the
+uncommitted `feat/python-to-legacy` work. Commit that branch first (still
+awaiting confirmation), then branch `fix/api-parity-vs-months-to-show` from
+it, with one commit per task. Open the MR with `tea` after the legacy move is
+merged, or target it at that branch.
+
+## Task 1 — VS (and other text cells) always a plain string in Go
+
+Root cause is `getVal` in `parseTransactionRows`
+(`go/internal/services/membership/sources.go`, the `fmt.Sprint(row[i])`
+closure). The same pattern exists in `get` in
+`go/internal/services/banksync/infer.go`.
+
+1. Add `CellString(v any) string` to `go/internal/io/sheets` (new small file
+   `cell.go`; both services already import this package):
+   - `nil` → `""`
+   - `float64` → `strconv.FormatFloat(x, 'f', -1, 64)` (never exponent form;
+     `2609767878.0` → `"2609767878"`, `12.5` → `"12.5"`)
+   - `string` → unchanged
+   - anything else → `fmt.Sprint(v)`
+2. Use it in `getVal` in `sources.go`. This fixes VS and protects the other
+   text columns (Message, Bank ID, Sender, …) from the same failure.
+   - `getVal` currently returns `"<nil>"` for nil cells and the inferred-amount
+     code checks for that literal; simplify that check to `iv != ""`.
+   - Leave `getRaw`/`FormatDate` and `parseFloat` for Date and Amount as they
+     are — those must stay numeric.
+3. Use it in `get` in `banksync/infer.go` (keeping the `TrimSpace`), so
+   inference sees the same text the dashboard shows.
+4. Tests:
+   - `go/internal/io/sheets/cell_test.go`: table test for `CellString`
+     (large integer float, small integer float, fractional, string with
+     leading zeros, nil).
+   - Extend `TestLoadTransactions` in
+     `go/internal/services/membership/sources_test.go` with a row whose VS is
+     `2609767878.0` and whose Bank ID is an 11-digit float; assert plain
+     digit strings.
+5. Python: no code change needed — `get_str` already does this for VS. Add one
+   regression test for `fetch_sheet_data` in
+   `legacy/tests/test_match_payments.py` (mock the Sheets service, numeric VS
+   cell → `"2609767878"`) so the two sides are pinned to the same behaviour.
+
+Not included (note for later): VS is *written* to the sheet with
+`USER_ENTERED` by both sync implementations, so Sheets stores it as a number
+and drops leading zeros. Fixing that means writing VS as text and is a
+separate change to the sheet's data.
+
+## Task 2 — backport `months_to_show` to the Python JSON API
+
+`legacy/app.py` only; `MONTHS_TO_SHOW` is already imported there.
+
+1. In `api_adults()` and `api_juniors()`, add the key to the response:
+   build `out = _unwrap_view_model_for_api(vm)`, set
+   `out["months_to_show"] = MONTHS_TO_SHOW`, return `jsonify(out)`.
+   - Do not add it inside `build_*_view_model` or `_unwrap_view_model_for_api`:
+     the HTML routes already pass `months_to_show=` to `render_template`
+     alongside `**vm`, and a duplicate key would raise `TypeError`.
+   - `/api/payments` is unchanged; Go does not return the key there.
+2. Tests in `legacy/tests/test_app.py`:
+   - Add `"months_to_show"` to the expected key list used by
+     `test_api_adults` / `test_api_juniors` (the tuple near the top of the
+     file), and assert the value is an `int`.
+3. Go: no change. The key and schemas
+   (`go/tests/fixtures/api-schema/{adults,juniors}.schema.json`) already
+   contain it.
+
+## Wrap-up
+
+- `CHANGELOG.md` entry at the top (after confirmation it works), per repo
+  convention.
+- Copy this plan to
+  `docs/plans/2026-10-08-HHMM-api-parity-vs-months-to-show.md`, per the repo's
+  plan-location rule.
+- Add both items to
+  `docs/plans/2026-10-08-1026-pre-feature-cleanup-tasks.md` as done tasks so
+  the audit list stays complete.
+
+## Verification
+
+1. `make go-test-all` — unit tests (including the new ones) and parity
+   fixtures pass.
+2. `make test` — Python tests pass, including the new API key and VS tests.
+3. `cd go && go test ./internal/web/api/...` — schema golden test still
+   matches (no schema change expected).
+4. End to end: start `make web-py` and `make web-go`, then `make parity`;
+   expect `3/3 routes match`. Alternatively repeat the two-container run used
+   to find the bugs (`make image`, Go image from `go/build/Dockerfile`, then
+   `go run ./cmd/parity -py … -go …`).
+5. Open `/payments` on :8080 and check the affected transaction's VS shows as
+   plain digits.

go/cmd/parity/main.go

@@ -21,7 +21,7 @@ var allRoutes = []string{"/api/adults", "/api/juniors", "/api/payments"}
 
 // defaultAllowlist holds dotted key paths to strip before diffing.
 // render_time.total is forward-compatible insurance: today it lives in the Jinja
-// template context only (app.py inject_render_time) and is logged via
+// template context only (legacy/app.py inject_render_time) and is logged via
 // middleware/timer.go on the Go side, so it isn't in any JSON response. If either
 // side ever surfaces it under a render_time envelope, the scrubber handles it.
 var defaultAllowlist = []string{"render_time.total"}

go/internal/config/config.go

@@ -42,7 +42,7 @@ const (
 	JuniorSheetGID          = "1213318614" // gid=1213318614 — junior practices tab (IMPORTRANGE'd)
 )
 
-// CacheSheetMap mirrors scripts/config.py CACHE_SHEET_MAP.
+// CacheSheetMap mirrors legacy/scripts/config.py CACHE_SHEET_MAP.
 // Maps a cache key to the Google Sheet ID whose Drive modifiedTime gates it.
 // Both attendance keys map to the same spreadsheet — different tabs, one Drive file.
 var CacheSheetMap = map[string]string{
@@ -53,7 +53,7 @@ var CacheSheetMap = map[string]string{
 }
 
 // Config holds all runtime configuration loaded from environment variables.
-// Mirrors scripts/config.py.
+// Mirrors legacy/scripts/config.py.
 type Config struct {
 	CredentialsPath  string
 	QRAccount        string          // IBAN of the primary account used for QR codes

go/internal/domain/czech/parse_month_references_test.go

@@ -9,7 +9,7 @@ func TestParseMonthReferences(t *testing.T) {
 	t.Parallel()
 
 	// All expected outputs verified against live Python implementation on 2026-05-05:
-	//   PYTHONPATH=scripts:. python -c 'from czech_utils import parse_month_references; print(parse_month_references("<input>", 2026))'
+	//   PYTHONPATH=legacy/scripts:legacy python -c 'from czech_utils import parse_month_references; print(parse_month_references("<input>", 2026))'
 	tests := []struct {
 		name        string
 		input       string

go/internal/domain/fees/fees.go

@@ -1,4 +1,4 @@
-// Package fees ports fee calculation from scripts/attendance.py.
+// Package fees ports fee calculation from legacy/scripts/attendance.py.
 package fees
 
 const (
@@ -6,7 +6,7 @@ const (
 	AdultFeeSingle  = 200 // CZK for exactly 1 practice
 )
 
-// AdultFeeMonthlyRate mirrors ADULT_FEE_MONTHLY_RATE in scripts/attendance.py.
+// AdultFeeMonthlyRate mirrors ADULT_FEE_MONTHLY_RATE in legacy/scripts/attendance.py.
 // Months absent from this map fall back to AdultFeeDefault.
 var AdultFeeMonthlyRate = map[string]int{
 	"2025-09": 750, "2025-10": 750, "2025-11": 750, "2025-12": 750,

go/internal/domain/fees/junior.go

@@ -2,7 +2,7 @@ package fees
 
 const JuniorFeeDefault = 500 // CZK fallback for 2+ practices when month not in JuniorFeeMonthlyRate
 
-// JuniorFeeMonthlyRate mirrors JUNIOR_MONTHLY_RATE in scripts/attendance.py.
+// JuniorFeeMonthlyRate mirrors JUNIOR_MONTHLY_RATE in legacy/scripts/attendance.py.
 // Months absent from this map fall back to JuniorFeeDefault.
 var JuniorFeeMonthlyRate = map[string]int{
 	"2025-09": 250,

go/internal/domain/matching/doc.go

@@ -1,2 +1,2 @@
-// Package matching ports name/member matching from scripts/match_payments.py.
+// Package matching ports name/member matching from legacy/scripts/match_payments.py.
 package matching

go/internal/domain/matching/format_date.go

@@ -14,7 +14,7 @@ var sheetsEpoch = time.Date(1899, 12, 30, 0, 0, 0, 0, time.UTC)
 // a pre-formatted "YYYY-MM-DD" string (returned as-is), or any other value
 // (returned as fmt.Sprint(v).TrimSpace). Never returns an error.
 //
-// Ports scripts/match_payments.py format_date.
+// Ports legacy/scripts/match_payments.py format_date.
 func FormatDate(val any) string {
 	if val == nil {
 		return ""

go/internal/domain/matching/format_date_test.go

@@ -1,8 +1,8 @@
 package matching
 
-// Expected values verified against scripts/match_payments.py on 2026-05-06:
+// Expected values verified against legacy/scripts/match_payments.py on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python3 -c '
+//	PYTHONPATH=legacy/scripts:legacy python3 -c '
 //	from match_payments import format_date
 //	for v in [None, "", 44197, 44197.5, "2026-04-15", "garbage", "  2026-04-15  "]:
 //	    print(repr(format_date(v)))

go/internal/domain/matching/infer.go

@@ -33,7 +33,7 @@ type InferredDetails struct {
 // defaultYear seeds czech.ParseMonthReferences (Python defaulted to the current year;
 // callers should pass time.Now().Year() or a fixed year for deterministic tests).
 //
-// Ports scripts/match_payments.py infer_transaction_details.
+// Ports legacy/scripts/match_payments.py infer_transaction_details.
 func InferTransactionDetails(tx Transaction, memberNames []string, defaultYear int) InferredDetails {
 	searchText := fmt.Sprintf("%s %s %s", tx.Sender, tx.Message, tx.UserID)
 

go/internal/domain/matching/infer_test.go

@@ -1,8 +1,8 @@
 package matching
 
-// Expected values verified against scripts/match_payments.py on 2026-05-06:
+// Expected values verified against legacy/scripts/match_payments.py on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python3 << 'EOF'
+//	PYTHONPATH=legacy/scripts:legacy python3 << 'EOF'
 //	from match_payments import infer_transaction_details
 //	MEMBERS = ["Tomáš Němeček (Tov)", "Jana Nováková"]
 //	cases = [

go/internal/domain/matching/match_members.go

@@ -28,7 +28,7 @@ var commonSurnames = map[string]bool{
 // MatchMembers finds members mentioned in text and returns them with a
 // confidence level of "auto" (reliable) or "review" (needs human verification).
 //
-// Algorithm (ported verbatim from scripts/match_payments.py match_members):
+// Algorithm (ported verbatim from legacy/scripts/match_payments.py match_members):
 //  1. Exact short-circuit: if any member's full normalized name appears as whole
 //     words in normalize(text), return ONLY those matches as auto. This prevents
 //     nickname "tov" from matching inside surname "ottova".

go/internal/domain/matching/match_members_test.go

@@ -1,9 +1,9 @@
 package matching
 
-// Expected values verified against scripts/match_payments.py and
+// Expected values verified against legacy/scripts/match_payments.py and
 // tests/test_match_members.py on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python3 -c '
+//	PYTHONPATH=legacy/scripts:legacy python3 -c '
 //	from match_payments import match_members
 //	MEMBERS = ["Henrietta Ottová", "Tomáš Němeček (Tov)", "František Vrbík (Štrúdl)", "Jana Nováková"]
 //	cases = [

go/internal/domain/matching/name_variants.go

@@ -19,7 +19,7 @@ var (
 // this invariant for the exact short-circuit pass. Variants shorter than 3 characters are
 // dropped.
 //
-// Ports scripts/match_payments.py _build_name_variants.
+// Ports legacy/scripts/match_payments.py _build_name_variants.
 func BuildNameVariants(name string) []string {
 	var nickname string
 	if m := nicknameRe.FindStringSubmatch(name); m != nil {

go/internal/domain/matching/name_variants_test.go

@@ -1,8 +1,8 @@
 package matching
 
-// Expected values verified against scripts/match_payments.py on 2026-05-06:
+// Expected values verified against legacy/scripts/match_payments.py on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python3 -c '
+//	PYTHONPATH=legacy/scripts:legacy python3 -c '
 //	from match_payments import _build_name_variants
 //	for n in ["František Vrbík (Štrúdl)", "Tov (St)", "Jana", "  Petr  Novák  ( Jenda ) "]:
 //	    print(repr(n), "->", _build_name_variants(n))

go/internal/domain/money/money.go

@@ -1,4 +1,4 @@
-// Package money ports Czech-locale currency parsing from scripts/infer_payments.py.
+// Package money ports Czech-locale currency parsing from legacy/scripts/infer_payments.py.
 package money
 
 import (
@@ -11,7 +11,7 @@ import (
 var ErrInvalidAmount = errors.New("money: invalid CZK amount")
 
 // ParseCZK parses a Czech-locale amount string and returns the value in CZK
-// as a float64. Mirrors scripts/infer_payments.py parse_czk_amount:
+// as a float64. Mirrors legacy/scripts/infer_payments.py parse_czk_amount:
 //
 //   - empty input → (0, nil)
 //   - "Kč"/"CZK" suffixes stripped (case-sensitive, like Python)

go/internal/domain/money/money_test.go

@@ -8,7 +8,7 @@ func TestParseCZK(t *testing.T) {
 	t.Parallel()
 
 	// All expected outputs verified against live Python implementation on 2026-05-06:
-	//   PYTHONPATH=scripts:. python -c '
+	//   PYTHONPATH=legacy/scripts:legacy python -c '
 	//   from infer_payments import parse_czk_amount
 	//   for v in [None, "", "0", "500", "500 Kč", "500 CZK",
 	//             "1 500", "1500.00", "1 500.00",

go/internal/domain/reconcile/reconcile.go

@@ -1,4 +1,4 @@
-// Package reconcile ports the three-phase payment reconciliation from scripts/match_payments.py.
+// Package reconcile ports the three-phase payment reconciliation from legacy/scripts/match_payments.py.
 package reconcile
 
 import (
@@ -105,7 +105,7 @@ var questionMarkRe = regexp.MustCompile(`\[\?\]\s*`)
 
 // canonicalMemberKey returns a diacritic-, case-, and whitespace-insensitive key
 // used to resolve Person-column values that drift from canonical attendance-sheet names.
-// Ports scripts/match_payments.py canonical_member_key.
+// Ports legacy/scripts/match_payments.py canonical_member_key.
 func canonicalMemberKey(name string) string {
 	return strings.Join(strings.Fields(czech.Normalize(name)), " ")
 }
@@ -124,7 +124,7 @@ type monthExpected struct {
 // defaultYear seeds czech.ParseMonthReferences in the inference fallback.
 // Pass time.Now().Year() in production; pass a fixed year in tests.
 //
-// Ports scripts/match_payments.py reconcile.
+// Ports legacy/scripts/match_payments.py reconcile.
 func Reconcile(
 	members []Member,
 	sortedMonths []string,

go/internal/domain/reconcile/reconcile_test.go

@@ -1,8 +1,8 @@
 package reconcile
 
-// Expected values verified against scripts/match_payments.py on 2026-05-06:
+// Expected values verified against legacy/scripts/match_payments.py on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python3 -m unittest tests.test_reconcile_exceptions tests.test_match_payments -v
+//	PYTHONPATH=legacy/scripts:legacy python3 -m unittest tests.test_reconcile_exceptions tests.test_match_payments -v
 //
 // All Python test cases are ported below. Additional Go-only cases are marked with [Go].
 

go/internal/domain/synch/synch.go

@@ -1,5 +1,5 @@
 // Package synch ports the bank-sync deduplication helper from
-// scripts/sync_fio_to_sheets.py.
+// legacy/scripts/sync_fio_to_sheets.py.
 package synch
 
 import (
@@ -30,7 +30,7 @@ type Transaction struct {
 // "date|amount|currency|sender|vs|message|bank_id" (lower-cased), used
 // as the dedup key in column K of the payments sheet.
 //
-// Byte-stable with scripts/sync_fio_to_sheets.py generate_sync_id.
+// Byte-stable with legacy/scripts/sync_fio_to_sheets.py generate_sync_id.
 func GenerateSyncID(tx Transaction) string {
 	currency := tx.Currency
 	if currency == "" {

go/internal/domain/synch/synch_test.go

@@ -6,7 +6,7 @@ import (
 
 // All expected digests verified against the live Python implementation on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python -c '
+//	PYTHONPATH=legacy/scripts:legacy python -c '
 //	from sync_fio_to_sheets import generate_sync_id
 //	cases = [
 //	    {"date":"2026-01-15","amount":500.0,"currency":"CZK","sender":"Jan Novak","vs":"123","message":"clenske 1/2026","bank_id":"abc123"},
@@ -88,7 +88,7 @@ func TestGenerateSyncID(t *testing.T) {
 
 // All expected strings verified against the live Python implementation on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python -c '
+//	PYTHONPATH=legacy/scripts:legacy python -c '
 //	for v in [0.0, 500.0, -500.0, 0.1, 1234.56, 99999.99, 1500000.0, 1e16, 1e-5]:
 //	    print(repr(v), "->", repr(str(v)))
 //	'

go/internal/io/cache/filecache.go

@@ -1,5 +1,5 @@
 // Package cache implements a Drive-modifiedTime-gated JSON file cache,
-// mirroring scripts/cache_utils.py.
+// mirroring legacy/scripts/cache_utils.py.
 package cache
 
 import (
@@ -26,7 +26,7 @@ type cacheFile struct {
 
 // FileCache wraps a Drive client to gate JSON file caching on sheet modifiedTime.
 //
-// Two TTL knobs mirror scripts/cache_utils.py:
+// Two TTL knobs mirror legacy/scripts/cache_utils.py:
 //   - ttl: if the cache file on disk is younger than this, skip the Drive check entirely.
 //   - apiCheckTTL: debounces in-memory Drive API calls per sheet ID.
 //

go/internal/io/fio/api.go

@@ -17,7 +17,7 @@ type httpDoer interface {
 }
 
 // apiClient fetches transactions from the Fio REST API (JSON).
-// Ports scripts/fio_utils.py fetch_transactions_api.
+// Ports legacy/scripts/fio_utils.py fetch_transactions_api.
 type apiClient struct {
 	token string
 	hc    httpDoer

go/internal/io/fio/transparent.go

@@ -15,7 +15,7 @@ import (
 )
 
 // transparentClient fetches transactions from the Fio transparent account page (HTML).
-// Ports scripts/fio_utils.py FioTableParser + fetch_transactions_transparent.
+// Ports legacy/scripts/fio_utils.py FioTableParser + fetch_transactions_transparent.
 type transparentClient struct {
 	accountNum string
 	hc         httpDoer

go/internal/io/sheets/cell.go

@@ -0,0 +1,33 @@
+package sheets
+
+import (
+	"fmt"
+	"strconv"
+)
+
+// CellString renders a cell read with UNFORMATTED_VALUE as text.
+// Numeric cells arrive as float64; fmt.Sprint would print large ones in
+// exponent form ("2.609767878e+09"), which corrupts identifiers such as VS
+// or Bank ID. Mirrors get_str in legacy/scripts/match_payments.py.
+func CellString(v any) string {
+	switch x := v.(type) {
+	case nil:
+		return ""
+	case string:
+		return x
+	case float64:
+		return strconv.FormatFloat(x, 'f', -1, 64)
+	}
+	return fmt.Sprint(v)
+}
+
+// TextCell marks s to be stored as text when written with USER_ENTERED:
+// a leading apostrophe stops Sheets from parsing digits as a number (which
+// would drop leading zeros). The apostrophe is not part of the stored value.
+// Empty stays empty. Mirrors as_text_cell in legacy/scripts/sync_fio_to_sheets.py.
+func TextCell(s string) string {
+	if s == "" {
+		return ""
+	}
+	return "'" + s
+}

go/internal/io/sheets/cell_test.go

@@ -0,0 +1,36 @@
+package sheets
+
+import "testing"
+
+func TestTextCell(t *testing.T) {
+	if got := TextCell("0308"); got != "'0308" {
+		t.Errorf(`TextCell("0308"): got %q`, got)
+	}
+	if got := TextCell(""); got != "" {
+		t.Errorf(`TextCell(""): got %q`, got)
+	}
+}
+
+func TestCellString(t *testing.T) {
+	cases := []struct {
+		name string
+		in   any
+		want string
+	}{
+		{"nil", nil, ""},
+		{"string", "fee", "fee"},
+		{"string with leading zeros", "0308", "0308"},
+		{"small integer float", 123.0, "123"},
+		{"large integer float", 2609767878.0, "2609767878"},
+		{"eleven digit float", 26123456789.0, "26123456789"},
+		{"fractional float", 12.5, "12.5"},
+		{"bool", true, "true"},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := CellString(tc.in); got != tc.want {
+				t.Errorf("CellString(%v): want %q, got %q", tc.in, tc.want, got)
+			}
+		})
+	}
+}

go/internal/services/banksync/infer.go

@@ -30,7 +30,7 @@ type sheetReadWriter interface {
 // InferPayments fills empty Person/Purpose/Inferred Amount cells in the payments
 // sheet using name and month matching against the member list.
 // Returns the number of rows updated (or that would be updated on dry-run).
-// Ports scripts/infer_payments.py infer_payments.
+// Ports legacy/scripts/infer_payments.py infer_payments.
 func InferPayments(
 	ctx context.Context,
 	spreadsheetID string,
@@ -94,7 +94,7 @@ func InferPayments(
 			if idx < 0 || idx >= len(row) {
 				return ""
 			}
-			return strings.TrimSpace(fmt.Sprint(row[idx]))
+			return strings.TrimSpace(sheets.CellString(row[idx]))
 		}
 
 		// Skip rule: any of manual fix / Person / Purpose non-empty → leave alone

go/internal/services/banksync/sync.go

@@ -6,13 +6,14 @@ import (
 	"fmt"
 	"fuj-management/go/internal/domain/synch"
 	"fuj-management/go/internal/io/fio"
+	"fuj-management/go/internal/io/sheets"
 	"os"
 	"strings"
 	"time"
 )
 
 // columnLabels is the canonical header for the payments sheet.
-// Mirrors COLUMN_LABELS in scripts/sync_fio_to_sheets.py.
+// Mirrors COLUMN_LABELS in legacy/scripts/sync_fio_to_sheets.py.
 var columnLabels = []string{
 	"Date", "Amount", "manual fix", "Person", "Purpose",
 	"Inferred Amount", "Sender", "VS", "Message", "Bank ID", "Sync ID",
@@ -37,7 +38,7 @@ type SyncOpts struct {
 
 // SyncToSheets fetches Fio transactions from all provided clients and appends
 // new ones to the payments sheet. Returns the number of rows appended.
-// Ports scripts/sync_fio_to_sheets.py sync_to_sheets.
+// Ports legacy/scripts/sync_fio_to_sheets.py sync_to_sheets.
 func SyncToSheets(
 	ctx context.Context,
 	spreadsheetID string,
@@ -130,7 +131,7 @@ func SyncToSheets(
 		newRows = append(newRows, []any{
 			tx.Date, tx.Amount,
 			"", "", "", "", // manual fix, Person, Purpose, Inferred Amount
-			tx.Sender, tx.VS, tx.Message, tx.BankID, syncIDs[i],
+			tx.Sender, sheets.TextCell(tx.VS), tx.Message, tx.BankID, syncIDs[i],
 		})
 	}
 
@@ -141,7 +142,7 @@ func SyncToSheets(
 	if opts.DryRun {
 		for _, row := range newRows {
 			fmt.Printf("Dry run: would append date=%v amount=%v sender=%v vs=%v message=%v\n",
-				row[0], row[1], row[6], row[7], row[8])
+				row[0], row[1], row[6], strings.TrimPrefix(fmt.Sprint(row[7]), "'"), row[8])
 		}
 		if opts.Sort {
 			fmt.Println("Dry run: would sort by date")

go/internal/services/banksync/sync_test.go

@@ -38,6 +38,10 @@ func TestSyncToSheets_EmptySheet(t *testing.T) {
 	if syncID, ok := rows[0][10].(string); !ok || len(syncID) != 64 {
 		t.Errorf("expected 64-char hex sync ID, got %v", rows[0][10])
 	}
+	// VS (index 7) is written as text so Sheets keeps it a string.
+	if vs, _ := rows[0][7].(string); vs != "'123" {
+		t.Errorf("expected VS written as text cell '123, got %v", rows[0][7])
+	}
 }
 
 func TestSyncToSheets_Dedup(t *testing.T) {

go/internal/services/membership/format_fees.go

@@ -9,11 +9,11 @@ import (
 )
 
 // printFeesTable writes a fixed-width adult-fees table to w.
-// Mirrors scripts/calculate_fees.py main().
+// Mirrors legacy/scripts/calculate_fees.py main().
 //
 // Verify with:
 //
-//	PYTHONPATH=scripts:. python scripts/calculate_fees.py
+//	PYTHONPATH=legacy/scripts:legacy python legacy/scripts/calculate_fees.py
 func printFeesTable(w io.Writer, members []reconcile.Member, sortedMonths []string) {
 	type row struct {
 		name string

go/internal/services/membership/format_fees_test.go

@@ -1,8 +1,8 @@
 package membership
 
-// Golden strings verified against scripts/calculate_fees.py on 2026-05-06:
+// Golden strings verified against legacy/scripts/calculate_fees.py on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python scripts/calculate_fees.py
+//	PYTHONPATH=legacy/scripts:legacy python legacy/scripts/calculate_fees.py
 //
 // (feed equivalent fixture data via attendance sheet or local CSV)
 

go/internal/services/membership/format_reconcile.go

@@ -10,11 +10,11 @@ import (
 )
 
 // printReconcileReport writes the full balance report to w.
-// Mirrors scripts/match_payments.py print_report().
+// Mirrors legacy/scripts/match_payments.py print_report().
 //
 // Verify with:
 //
-//	PYTHONPATH=scripts:. python -c '
+//	PYTHONPATH=legacy/scripts:legacy python -c '
 //	from match_payments import print_report, reconcile, fetch_sheet_data, fetch_exceptions
 //	...'
 func printReconcileReport(w io.Writer, result reconcile.Result, sortedMonths []string) {

go/internal/services/membership/format_reconcile_test.go

@@ -1,8 +1,8 @@
 package membership
 
-// Golden strings verified against scripts/match_payments.py print_report() on 2026-05-06:
+// Golden strings verified against legacy/scripts/match_payments.py print_report() on 2026-05-06:
 //
-//	PYTHONPATH=scripts:. python -c '
+//	PYTHONPATH=legacy/scripts:legacy python -c '
 //	from match_payments import print_report
 //	result = {
 //	  "members": {

go/internal/services/membership/sources.go

@@ -18,20 +18,20 @@ import (
 	"time"
 )
 
-// Attendance CSV column indices (mirrors COL_* in scripts/attendance.py)
+// Attendance CSV column indices (mirrors COL_* in legacy/scripts/attendance.py)
 const (
 	colName      = 0
 	colTier      = 1
 	firstDateCol = 3
 )
 
-// AdultMergedMonths mirrors ADULT_MERGED_MONTHS in scripts/attendance.py.
+// AdultMergedMonths mirrors ADULT_MERGED_MONTHS in legacy/scripts/attendance.py.
 // Source month → target month (source attendance accumulated into target).
 var AdultMergedMonths = map[string]string{
 	"2025-09": "2025-10",
 }
 
-// JuniorMergedMonths mirrors JUNIOR_MERGED_MONTHS in scripts/attendance.py.
+// JuniorMergedMonths mirrors JUNIOR_MERGED_MONTHS in legacy/scripts/attendance.py.
 var JuniorMergedMonths = map[string]string{
 	"2025-12": "2026-01",
 	"2025-09": "2025-10",
@@ -127,11 +127,11 @@ func (s *realSources) LoadExceptions(ctx context.Context) (map[reconcile.Excepti
 }
 
 // ---------------------------------------------------------------------------
-// Attendance CSV parsing (ports scripts/attendance.py)
+// Attendance CSV parsing (ports legacy/scripts/attendance.py)
 // ---------------------------------------------------------------------------
 
 // parseDates returns (columnIndex, YYYY-MM) pairs for all date columns.
-// Ports scripts/attendance.py parse_dates + strftime("%Y-%m").
+// Ports legacy/scripts/attendance.py parse_dates + strftime("%Y-%m").
 func parseDates(header []string) []struct {
 	col   int
 	month string
@@ -200,7 +200,7 @@ func countTrue(row []string, cols []int) int {
 
 // parseAdultRows converts raw CSV rows to []reconcile.Member.
 // Includes all tiers; fee is 0 for non-A tiers (reconcile filters downstream).
-// Ports scripts/attendance.py get_members_with_fees.
+// Ports legacy/scripts/attendance.py get_members_with_fees.
 func parseAdultRows(rows [][]string) ([]reconcile.Member, []string, error) {
 	if len(rows) < 2 {
 		return nil, nil, nil
@@ -246,7 +246,7 @@ func parseAdultRows(rows [][]string) ([]reconcile.Member, []string, error) {
 
 // parseJuniorRows builds junior members by merging tier-J rows from the adult tab
 // with the junior sheet, then calling CalculateJuniorFee.
-// Ports scripts/attendance.py get_junior_members_with_fees.
+// Ports legacy/scripts/attendance.py get_junior_members_with_fees.
 func parseJuniorRows(adultRows, juniorRows [][]string) ([]reconcile.Member, []string, error) {
 	if len(adultRows) < 2 || len(juniorRows) < 2 {
 		return nil, nil, nil
@@ -362,7 +362,7 @@ func parseJuniorRows(adultRows, juniorRows [][]string) ([]reconcile.Member, []st
 }
 
 // ---------------------------------------------------------------------------
-// Payments sheet row parsing (ports scripts/match_payments.py fetch_sheet_data)
+// Payments sheet row parsing (ports legacy/scripts/match_payments.py fetch_sheet_data)
 // ---------------------------------------------------------------------------
 
 func parseTransactionRows(rows [][]any) ([]reconcile.Transaction, error) {
@@ -402,7 +402,7 @@ func parseTransactionRows(rows [][]any) ([]reconcile.Transaction, error) {
 		if i < 0 || i >= len(row) {
 			return ""
 		}
-		return fmt.Sprint(row[i])
+		return sheets.CellString(row[i])
 	}
 
 	// getRaw returns row[i] without stringifying — needed for FormatDate to
@@ -425,7 +425,7 @@ func parseTransactionRows(rows [][]any) ([]reconcile.Transaction, error) {
 		amount := parseFloat(amountRaw)
 
 		var inferredAmount *float64
-		if iv := getVal(row, idxInferred); iv != "" && iv != "<nil>" {
+		if iv := getVal(row, idxInferred); iv != "" {
 			if f := parseFloat(iv); f != 0 {
 				inferredAmount = &f
 			}
@@ -466,7 +466,7 @@ func parseFloat(v any) float64 {
 }
 
 // ---------------------------------------------------------------------------
-// Exceptions tab parsing (ports scripts/match_payments.py fetch_exceptions)
+// Exceptions tab parsing (ports legacy/scripts/match_payments.py fetch_exceptions)
 // ---------------------------------------------------------------------------
 
 func parseExceptionRows(rows [][]any) map[reconcile.ExceptionKey]reconcile.Exception {

go/internal/services/membership/sources_test.go

@@ -123,6 +123,8 @@ func TestLoadTransactions(t *testing.T) {
 			{"Date", "Amount", "manual fix", "Person", "Purpose", "Inferred Amount", "Sender", "VS", "Message", "Bank ID", "Sync ID"},
 			{"2026-04-01", 700.0, "", "Alice", "2026-04", "", "Alice Bank", "", "fee", "", "abc"},
 			{46147.0, 500.0, "", "", "", "", "Bob Bank", "", "platba", "", "def"}, // 46147 serial-day = 2026-05-05
+			// Numeric VS / Bank ID cells arrive as float64 and must stay plain digits.
+			{"2026-05-06", 500.0, "", "", "", "", "Carol Bank", 2609767878.0, "platba", 26123456789.0, "ghi"},
 		},
 	}}
 	s := buildSources(t, &attendance.Fake{}, sh)
@@ -131,8 +133,8 @@ func TestLoadTransactions(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if len(txns) != 2 {
+	if len(txns) != 3 {
-		t.Fatalf("want 2 transactions, got %d", len(txns))
+		t.Fatalf("want 3 transactions, got %d", len(txns))
 	}
 	if txns[0].Person != "Alice" {
 		t.Errorf("txn[0].Person: want Alice, got %q", txns[0].Person)
@@ -146,6 +148,12 @@ func TestLoadTransactions(t *testing.T) {
 	if txns[1].Date != "2026-05-05" {
 		t.Errorf("txn[1].Date (numeric serial-day): want 2026-05-05, got %q", txns[1].Date)
 	}
+	if txns[2].VS != "2609767878" {
+		t.Errorf("txn[2].VS (numeric cell): want 2609767878, got %q", txns[2].VS)
+	}
+	if txns[2].BankID != "26123456789" {
+		t.Errorf("txn[2].BankID (numeric cell): want 26123456789, got %q", txns[2].BankID)
+	}
 }
 
 func TestLoadExceptions(t *testing.T) {

go/internal/web/api/build_adults.go

@@ -13,7 +13,7 @@ import (
 type monthSums struct{ expected, paid int }
 
 // buildAdultsResponse constructs the AdultsResponse wire type from reconcile output.
-// Mirrors scripts/views.py:build_adults_view_model.
+// Mirrors legacy/scripts/views.py:build_adults_view_model.
 func buildAdultsResponse(
 	members []domreconcile.Member,
 	sortedMonths []string,

go/internal/web/api/build_common.go

@@ -12,7 +12,7 @@ import (
 
 // getMonthLabels builds display labels for sortedMonths, merging month names
 // (e.g. "Dec+Jan 2026") when mergedMonths maps a source month into this target.
-// Mirrors scripts/views.py:get_month_labels.
+// Mirrors legacy/scripts/views.py:get_month_labels.
 func getMonthLabels(sortedMonths []string, mergedMonths map[string]string) map[string]string {
 	labels := make(map[string]string, len(sortedMonths))
 	for _, m := range sortedMonths {
@@ -72,14 +72,14 @@ func labelsForMonths(sortedMonths []string, labels map[string]string) []string {
 var questionMarkRe = regexp.MustCompile(`\[\?\]\s*`)
 
 // canonicalKey returns a normalized form of a person name used for deduplication.
-// Mirrors scripts/match_payments.py:canonical_member_key.
+// Mirrors legacy/scripts/match_payments.py:canonical_member_key.
 func canonicalKey(name string) string {
 	return strings.Join(strings.Fields(czech.Normalize(name)), " ")
 }
 
 // groupRawPaymentsByPerson groups transactions by the "person" column,
 // canonicalizing names against memberNames where possible.
-// Mirrors scripts/views.py:group_payments_by_person (without the
+// Mirrors legacy/scripts/views.py:group_payments_by_person (without the
 // "Unmatched / Unknown" bucket that is payments-view-specific).
 func groupRawPaymentsByPerson(txns []domreconcile.Transaction, memberNames []string) map[string][]RawTransaction {
 	canonicalByKey := make(map[string]string, len(memberNames))

go/internal/web/api/build_juniors.go

@@ -11,7 +11,7 @@ import (
 )
 
 // buildJuniorsResponse constructs the JuniorsResponse wire type from reconcile output.
-// Mirrors scripts/views.py:build_juniors_view_model.
+// Mirrors legacy/scripts/views.py:build_juniors_view_model.
 func buildJuniorsResponse(
 	members []domreconcile.Member,
 	sortedMonths []string,

go/internal/web/api/build_payments.go

@@ -9,7 +9,7 @@ import (
 )
 
 // buildPaymentsResponse constructs the PaymentsResponse wire type.
-// Mirrors scripts/views.py:build_payments_view_model.
+// Mirrors legacy/scripts/views.py:build_payments_view_model.
 func buildPaymentsResponse(
 	txns []domreconcile.Transaction,
 	memberNames []string,

go/internal/web/api/version.go

@@ -1,7 +1,7 @@
 package api
 
 // VersionResponse is the JSON contract for GET /api/version.
-// Keys match Python's BUILD_META dict (see app.py).
+// Keys match Python's BUILD_META dict (see legacy/app.py).
 type VersionResponse struct {
 	Tag       string `json:"tag"`
 	Commit    string `json:"commit"`

go/tests/fixtures/README.md

@@ -85,10 +85,10 @@ git diff go/tests/fixtures/   # review changes before committing
 To refresh a single function:
 
 ```bash
-PYTHONPATH=scripts:. python3 scripts/capture_fixtures.py --func normalize --all \
+PYTHONPATH=legacy/scripts:legacy python3 legacy/scripts/capture_fixtures.py --func normalize --all \
   | while IFS= read -r line; do
       id=$(echo "$line" | python3 -c "import sys,json; print(json.load(sys.stdin)['case'])")
-      echo "$line" | python3 scripts/scrub_fixtures.py \
+      echo "$line" | python3 legacy/scripts/scrub_fixtures.py \
         > go/tests/fixtures/pure/normalize/${id}.json
     done
 ```
@@ -120,7 +120,7 @@ verify that no real roster names appear in their `member_names` arrays.
 
 ## Adding a new fixture
 
-1. Add a seed to `scripts/_fixture_seeds.py` under `SEEDS[("func_name", "case_id")]`.
+1. Add a seed to `legacy/scripts/_fixture_seeds.py` under `SEEDS[("func_name", "case_id")]`.
 2. Add `In`/`Out` struct fields to `go/tests/parity/parityio.go` if the function
    is new.
 3. Run the single-file capture recipe above and review the diff.

go/tests/parity/pure/build_name_variants/build_name_variants_parity_test.go

@@ -13,7 +13,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "from match_payments import _build_name_variants; print(_build_name_variants('František Vrbík (Štrúdl)'))"
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "from match_payments import _build_name_variants; print(_build_name_variants('František Vrbík (Štrúdl)'))"
 
 func TestBuildNameVariantsParity(t *testing.T) {
 	t.Parallel()

go/tests/parity/pure/calculate_fee/calculate_fee_parity_test.go

@@ -12,7 +12,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "from attendance import calculate_fee; print(calculate_fee(2, '2026-01'))"
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "from attendance import calculate_fee; print(calculate_fee(2, '2026-01'))"
 
 func TestCalculateFeeParity(t *testing.T) {
 	t.Parallel()

go/tests/parity/pure/calculate_junior_fee/calculate_junior_fee_parity_test.go

@@ -12,7 +12,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "from attendance import calculate_junior_fee; print(calculate_junior_fee(1, '2026-01'))"
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "from attendance import calculate_junior_fee; print(calculate_junior_fee(1, '2026-01'))"
 
 func TestCalculateJuniorFeeParity(t *testing.T) {
 	t.Parallel()

go/tests/parity/pure/format_date/format_date_parity_test.go

@@ -12,7 +12,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "from match_payments import format_date; print(format_date(46027))"
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "from match_payments import format_date; print(format_date(46027))"
 
 func TestFormatDateParity(t *testing.T) {
 	t.Parallel()

go/tests/parity/pure/generate_sync_id/generate_sync_id_parity_test.go

@@ -12,7 +12,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "
 //	from sync_fio_to_sheets import generate_sync_id
 //	print(generate_sync_id({'date':'2026-01-15','amount':750.0,'currency':'CZK','sender':'Test','vs':'123','message':'x','bank_id':'1'}))"
 //

go/tests/parity/pure/infer_transaction_details/infer_transaction_details_parity_test.go

@@ -12,7 +12,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "
 //	from match_payments import infer_transaction_details
 //	print(infer_transaction_details({'sender':'Henrietta Ottová','message':'leden 2026','user_id':'','date':'2026-01-15'}, ['Henrietta Ottová']))"
 

go/tests/parity/pure/match_members/match_members_parity_test.go

@@ -12,7 +12,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "from match_payments import match_members; print(match_members('henrietta ottova leden', ['Henrietta Ottová','Jan Novák']))"
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "from match_payments import match_members; print(match_members('henrietta ottova leden', ['Henrietta Ottová','Jan Novák']))"
 
 func TestMatchMembersParity(t *testing.T) {
 	t.Parallel()

go/tests/parity/pure/normalize/normalize_parity_test.go

@@ -12,7 +12,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "from czech_utils import normalize; print(normalize('štefan čakrtový'))"
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "from czech_utils import normalize; print(normalize('štefan čakrtový'))"
 
 func TestNormalizeParity(t *testing.T) {
 	t.Parallel()

go/tests/parity/pure/parse_czk_amount/parse_czk_amount_parity_test.go

@@ -12,7 +12,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "from infer_payments import parse_czk_amount; print(parse_czk_amount('1.500,00'))"
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "from infer_payments import parse_czk_amount; print(parse_czk_amount('1.500,00'))"
 //
 // Note: Go's ParseCZK returns an error for unparseable input; Python returns 0.0.
 // Callers should discard the error to match Python semantics: v, _ := money.ParseCZK(s)

go/tests/parity/pure/parse_month_references/parse_month_references_parity_test.go

@@ -13,7 +13,7 @@ import (
 
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "from czech_utils import parse_month_references; print(parse_month_references('prosinec-leden', 2026))"
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "from czech_utils import parse_month_references; print(parse_month_references('prosinec-leden', 2026))"
 
 func TestParseMonthReferencesParity(t *testing.T) {
 	t.Parallel()

go/tests/parity/reconcile/reconcile_parity_test.go

@@ -6,7 +6,7 @@
 //
 // Verify expected values against live Python:
 //
-//	PYTHONPATH=scripts:. python3 -c "
+//	PYTHONPATH=legacy/scripts:legacy python3 -c "
 //	from match_payments import reconcile
 //	# ... build members/months/txs/exceptions...
 //	import json; print(json.dumps(reconcile(...)))"

legacy/.dockerignore

@@ -1,6 +1,6 @@
 .git
 .venv
-__pycache__
+**/__pycache__
-*.pyc
+**/*.pyc
 .claude
 .gemini

legacy/app.py

@@ -179,7 +179,9 @@ def api_adults():
         datetime.now().strftime("%Y-%m"),
         attendance_url=attendance_url, payments_url=payments_url, bank_account=BANK_ACCOUNT,
     )
-    return jsonify(_unwrap_view_model_for_api(vm))
+    out = _unwrap_view_model_for_api(vm)
+    out["months_to_show"] = MONTHS_TO_SHOW
+    return jsonify(out)
 
 @app.route("/api/juniors")
 def api_juniors():
@@ -203,7 +205,9 @@ def api_juniors():
         datetime.now().strftime("%Y-%m"),
         attendance_url=attendance_url, payments_url=payments_url, bank_account=BANK_ACCOUNT,
     )
-    return jsonify(_unwrap_view_model_for_api(vm))
+    out = _unwrap_view_model_for_api(vm)
+    out["months_to_show"] = MONTHS_TO_SHOW
+    return jsonify(out)
 
 @app.route("/api/payments")
 def api_payments():

legacy/build/Dockerfile

@@ -17,7 +17,7 @@ RUN pip install --no-cache-dir \
     pillow \
     gunicorn
 
-COPY app.py Makefile ./
+COPY app.py ./
 COPY scripts/ ./scripts/
 COPY templates/ ./templates/
 

legacy/pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "fuj-management"
 version = "0.10"
-description = "Management tools for FUJ (Frisbee Ultimate Jablonec)"
+description = "Legacy Python implementation of the FUJ (Frisbee Ultimate Jablonec) management tools; the Go implementation in ../go is primary"
 dependencies = [
     "flask>=3.1.3",
     "google-api-python-client>=2.162.0",

legacy/scripts/capture_all_fixtures.sh

@@ -1,14 +1,15 @@
 #!/usr/bin/env bash
 # Regenerate the full fixture corpus.
 # Safe to re-run — always overwrites.
-# Requires: tmp/*_cache.json present (for real-data seeds for parse_month_references and match_members).
+# Requires: legacy/tmp/*_cache.json present (for real-data seeds for parse_month_references and match_members).
 
 set -euo pipefail
 
-REPO="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+LEGACY="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+REPO="$(cd "$LEGACY/.." && pwd)"
 FIXTURES="$REPO/go/tests/fixtures"
-CAPTURE_CMD="PYTHONPATH=$REPO/scripts:. python3 $REPO/scripts/capture_fixtures.py"
+CAPTURE_CMD="PYTHONPATH=$LEGACY/scripts:$LEGACY python3 $LEGACY/scripts/capture_fixtures.py"
-SCRUB_CMD="python3 $REPO/scripts/scrub_fixtures.py"
+SCRUB_CMD="python3 $LEGACY/scripts/scrub_fixtures.py"
 
 run_func() {
     local func="$1"
@@ -18,7 +19,7 @@ run_func() {
     eval "$CAPTURE_CMD --func $func --all" | while IFS= read -r line; do
         case_id="$(python3 -c "import sys,json; print(json.loads('''$line''')['case'])" 2>/dev/null || \
                    echo "$line" | python3 -c "import sys,json; d=json.load(sys.stdin); print(d['case'])")"
-        echo "$line" | python3 "$REPO/scripts/scrub_fixtures.py" > "$dir/${case_id}.json"
+        echo "$line" | python3 "$LEGACY/scripts/scrub_fixtures.py" > "$dir/${case_id}.json"
     done
 }
 
@@ -39,7 +40,7 @@ echo "==> Capturing reconcile fixtures..."
 mkdir -p "$FIXTURES/reconcile"
 eval "$CAPTURE_CMD --func reconcile --all" | while IFS= read -r line; do
     case_id="$(echo "$line" | python3 -c "import sys,json; d=json.load(sys.stdin); print(d['case'])")"
-    echo "$line" | python3 "$REPO/scripts/scrub_fixtures.py" > "$FIXTURES/reconcile/${case_id}.json"
+    echo "$line" | python3 "$LEGACY/scripts/scrub_fixtures.py" > "$FIXTURES/reconcile/${case_id}.json"
 done
 
 echo "==> Done. Review with: git diff go/tests/fixtures/"

legacy/scripts/sync_fio_to_sheets.py

@@ -59,6 +59,16 @@ def get_sheets_service(credentials_path: str):
     return _SHEETS_SERVICE
 
 
+def as_text_cell(value) -> str:
+    """Mark a value to be stored as text when written with USER_ENTERED.
+
+    A leading apostrophe stops Sheets from parsing digits as a number (which
+    would drop leading zeros); it is not part of the stored value. Empty stays empty.
+    """
+    s = "" if value is None else str(value)
+    return f"'{s}" if s else ""
+
+
 def generate_sync_id(tx: dict) -> str:
     """Generate a unique SHA-256 hash for a transaction.
     
@@ -209,7 +219,7 @@ def sync_to_sheets(
                 "", # Purpose
                 "", # Inferred Amount
                 tx.get("sender", ""),
-                tx.get("vs", ""),
+                as_text_cell(tx.get("vs", "")),
                 tx.get("message", ""),
                 tx.get("bank_id", ""),
                 sync_id,

legacy/tests/test_app.py

@@ -6,7 +6,7 @@ from app import app
 EXPECTED_ADULTS_KEYS = {
     "months", "raw_months", "results", "totals", "member_data", "month_labels",
     "raw_payments", "credits", "debts", "unmatched", "attendance_url",
-    "payments_url", "bank_account", "current_month",
+    "payments_url", "bank_account", "current_month", "months_to_show",
 }
 EXPECTED_JUNIORS_KEYS = EXPECTED_ADULTS_KEYS
 EXPECTED_PAYMENTS_KEYS = {"grouped_payments", "sorted_people", "attendance_url", "payments_url"}
@@ -139,6 +139,7 @@ class TestWebApp(unittest.TestCase):
         self.assertIsInstance(data['member_data'], dict)
         self.assertIsInstance(data['month_labels'], dict)
         self.assertIsInstance(data['raw_payments'], dict)
+        self.assertIsInstance(data['months_to_show'], int)
 
     @patch('app.get_cached_data', side_effect=_bypass_cache)
     @patch('app.fetch_sheet_data')
@@ -166,6 +167,7 @@ class TestWebApp(unittest.TestCase):
         self.assertIsInstance(data['member_data'], dict)
         self.assertIsInstance(data['month_labels'], dict)
         self.assertIsInstance(data['raw_payments'], dict)
+        self.assertIsInstance(data['months_to_show'], int)
 
     @patch('app.get_cached_data', side_effect=_bypass_cache)
     @patch('app.fetch_sheet_data')

legacy/tests/test_match_payments.py

@@ -1,6 +1,7 @@
 import unittest
+from unittest.mock import MagicMock, patch
 
-from scripts.match_payments import canonical_member_key, reconcile
+from scripts.match_payments import canonical_member_key, fetch_sheet_data, reconcile
 
 
 class TestCanonicalMemberKey(unittest.TestCase):
@@ -67,3 +68,23 @@ class TestReconcileTolerantPersonMatching(unittest.TestCase):
 
 if __name__ == "__main__":
     unittest.main()
+
+
+class TestFetchSheetDataVS(unittest.TestCase):
+    """Numeric VS cells arrive as floats (UNFORMATTED_VALUE) and must stay plain digit strings."""
+
+    def _fetch(self, vs_cell):
+        service = MagicMock()
+        service.spreadsheets().values().get().execute.return_value = {"values": [
+            ["Date", "Amount", "manual fix", "Person", "Purpose", "Inferred Amount",
+             "Sender", "VS", "Message", "Bank ID", "Sync ID"],
+            ["2026-04-15", 750, "", "", "", "", "Test Sender", vs_cell, "fee", "", "abc"],
+        ]}
+        with patch("scripts.match_payments.get_sheets_service", return_value=service):
+            return fetch_sheet_data("sheet-id", "creds.json")
+
+    def test_numeric_vs_is_plain_digit_string(self):
+        self.assertEqual(self._fetch(2609767878.0)[0]["vs"], "2609767878")
+
+    def test_string_vs_is_kept(self):
+        self.assertEqual(self._fetch("0308")[0]["vs"], "0308")

legacy/tests/test_sync_fio.py

@@ -0,0 +1,33 @@
+import contextlib
+import io
+import unittest
+from unittest.mock import MagicMock, patch
+
+from scripts.sync_fio_to_sheets import COLUMN_LABELS, as_text_cell, sync_to_sheets
+
+
+class TestAsTextCell(unittest.TestCase):
+    def test_digits_get_text_marker(self):
+        self.assertEqual(as_text_cell("0308"), "'0308")
+        self.assertEqual(as_text_cell(123), "'123")
+
+    def test_empty_stays_empty(self):
+        self.assertEqual(as_text_cell(""), "")
+        self.assertEqual(as_text_cell(None), "")
+
+
+class TestSyncWritesVSAsText(unittest.TestCase):
+    def test_appended_row_has_text_vs(self):
+        service = MagicMock()
+        sheet = service.spreadsheets.return_value
+        sheet.values.return_value.get.return_value.execute.return_value = {"values": [COLUMN_LABELS]}
+        tx = {"date": "2026-04-10", "amount": 750.0, "sender": "Test Sender",
+              "vs": "0308", "message": "fee", "bank_id": "111"}
+        with patch("scripts.sync_fio_to_sheets.get_sheets_service", return_value=service), \
+             patch("scripts.sync_fio_to_sheets.fetch_transactions_all", return_value=[tx]), \
+             contextlib.redirect_stdout(io.StringIO()):
+            sync_to_sheets("sheet-id", "creds.json", days=30)
+
+        body = sheet.values.return_value.append.call_args.kwargs["body"]
+        self.assertEqual(len(body["values"]), 1)
+        self.assertEqual(body["values"][0][7], "'0308")