chore: tick M2.3 + M2.4 in progress tracker + CHANGELOG entry

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Merge pull request 'feat(go/M2.3+M2.4): port domain/fees.CalculateFee and CalculateJuniorFee' (#6 ) from feat/m2-3-m2-4-domain-fees into main
2026-05-06 09:25:45 +02:00 · 2026-05-06 07:23:02 +00:00 · 2026-05-06 00:38:09 +02:00 · 2026-05-06 00:29:19 +02:00 · 2026-05-06 00:10:44 +02:00 · 2026-05-05 22:07:15 +00:00
16 changed files with 1110 additions and 7 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,23 @@
 # Changelog

+## 2026-05-06 09:24 CEST — feat(go/M2.3+M2.4): port domain/fees.CalculateFee and CalculateJuniorFee
+
+- New `go/internal/domain/fees` package with adult and junior fee calculators ported from `scripts/attendance.py`.
+- `CalculateFee(count, monthKey) int` — `0→0`, `1→200`, `2+→AdultFeeMonthlyRate[month]` (fallback 700 CZK).
+- `CalculateJuniorFee(count, monthKey) Expected` — `0→{0}`, `1→{Unknown:true}` (the `"?"` sentinel, now strictly typed), `2+→JuniorFeeMonthlyRate[month]` (fallback 500 CZK).
+- 20 table-driven tests, all verified against live Python; `-race` clean; `golangci-lint` clean.
+
+## 2026-05-06 00:07 CEST — feat(go/M2.2): port czech.ParseMonthReferences
+
+- `internal/domain/czech.ParseMonthReferences`: three-pass regex (numeric slash, dot, Czech month names) with range wrap-around and `m≥10 → previousYear` heuristic, byte-equivalent to Python.
+- 35 table-driven tests; all expected outputs verified against live Python before locking (addresses risk #4 from the rewrite plan).
+
+## 2026-05-05 23:33 CEST — feat(go/M2.1): port czech.Normalize
+
+- First M2 pure-domain task: `internal/domain/czech.Normalize` (NFKD + Mn-strip + lowercase), byte-equivalent to Python `czech_utils.normalize`.
+- Adds `golang.org/x/text v0.36.0` as first external Go dependency.
+- 13-case table-driven test, all spot-checked against Python before locking.
+
 ## 2026-05-04 23:08 CEST — fix: payment inference exact-match short-circuit

 - `match_members()` now short-circuits on whole-word full-name hits; nickname/partial checks only run when no full name is present.
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -64,13 +64,13 @@ Fio Bank API               ──► sync_fio_to_sheets.py ──► Google Shee
 ### Member tiers

 Tiers are set in column B of the attendance sheet:
- `A` — Adult, pays fees (750 CZK/month for 2+ sessions, 200 CZK for exactly 1)
+- `A` — Adult, pays fees (per-month rate from `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.)

 ### Fee calculation

- Adults: 0 sessions → 0, 1 session → 200 CZK, 2+ sessions → monthly rate (default 750 CZK)
+- Adults: 0 sessions → 0, 1 session → 200 CZK, 2+ sessions → monthly rate (default 700 CZK)
 - Juniors: 0 → 0, 1 → `"?"` (manual review required), 2+ → monthly rate (default 500 CZK)
 - Per-member per-month overrides live in the `exceptions` tab of the payments sheet (columns: Name, Period YYYY-MM, Amount, Note). Exceptions are keyed by `(normalize(name), normalize(period))`.

@@ -92,6 +92,45 @@ Tiers are set in column B of the attendance sheet:

 `/qr?account=…&amount=…&message=…` generates a Czech QR Platba PNG (SPD format).

+## Branching & merge requests
+
+The remote is Gitea (`gitea.home.hrajfrisbee.cz/kacerr/fuj-management`).
+For **features**, do not commit to `main` directly. Use a branch + merge
+request flow:
+
+1. **Create a branch off `main`** before starting work:
+   - `feat/<slug>` for features (e.g. `feat/qr-code-overlay`)
+   - `fix/<slug>` for bug-fix branches the user explicitly asks for
+   - `<slug>` is short kebab-case
+2. **Commit on the branch** following the existing commit conventions
+   (Co-Authored-By trailer, etc.).
+3. **Push the branch** to `origin` with `-u` so it tracks.
+4. **Open the MR with `tea`** rather than printing a compare URL:
+
+   ```bash
+   tea pr create \
+     --title "<short title>" \
+     --description "<body>" \
+     --base main \
+     --head <branch>
+   ```
+
+   `tea` is already authenticated against the Gitea instance; just run it.
+   Print the resulting PR URL for the user. If `tea` is unavailable for
+   some reason, fall back to printing the compare URL
+   (`https://gitea.home.hrajfrisbee.cz/kacerr/fuj-management/compare/main...<branch>`)
+   and let the user open the MR manually.
+5. **Do not merge or delete the branch** from the CLI — neither via `tea`,
+   `gh`, nor `git push --delete`. The user does that in Gitea.
+
+**Exceptions — when committing straight to `main` is fine:**
+- Small bug fixes / hotfixes the user describes as such.
+- Typo / comment / formatting tweaks.
+- Edits the user explicitly says to push to `main`.
+
+When uncertain whether something is a feature or a small fix, ask before
+committing.
+
 ## Git Commits

 When making git commits, always append yourself as co-author trailer to the end of the commit message to indicate AI assistance
--- a/docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md
+++ b/docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md
@@ -4,7 +4,7 @@ Companion to [2026-05-03-2349-go-backend-rewrite.md](2026-05-03-2349-go-backend-

 **Current milestone:** M2 — Pure-domain helpers
 **Started:** 2026-05-04
-**Last updated:** 2026-05-04
+**Last updated:** 2026-05-06

 ## How to use

@@ -44,10 +44,10 @@ Goal: every pure function from the Python backend exists in Go with a parity tes

 Each task: port the function, write Go unit tests for fresh cases, hook into the Tier-1 parity runner.

- [ ] **M2.1** `domain/czech.Normalize` — port [czech_utils.py](scripts/czech_utils.py) `normalize` (NFKD + combining-mark strip + lowercase)
- [ ] **M2.2** `domain/czech.ParseMonthReferences` — port `parse_month_references` (45 month declensions, range wrap, year inference)
- [ ] **M2.3** `domain/fees.CalculateFee` — port [attendance.py](scripts/attendance.py) `calculate_fee` (constants table)
- [ ] **M2.4** `domain/fees.CalculateJuniorFee` — port `calculate_junior_fee` with `Expected{Value int; Unknown bool}` for the `"?"` sentinel
+- [x] **M2.1** `domain/czech.Normalize` — port [czech_utils.py](scripts/czech_utils.py) `normalize` (NFKD + combining-mark strip + lowercase) — `20ade6d`
+- [x] **M2.2** `domain/czech.ParseMonthReferences` — port `parse_month_references` (45 month declensions, range wrap, year inference) — `0a8017f`
+- [x] **M2.3** `domain/fees.CalculateFee` — port [attendance.py](scripts/attendance.py) `calculate_fee` (constants table) — `0fc3b6d`
+- [x] **M2.4** `domain/fees.CalculateJuniorFee` — port `calculate_junior_fee` with `Expected{Value int; Unknown bool}` for the `"?"` sentinel — `0fc3b6d`
 - [ ] **M2.5** `domain/money.ParseCZK` — port [infer_payments.py](scripts/infer_payments.py) `parse_czk_amount` (Czech locale: comma decimal, dot/space thousand separators)
 - [ ] **M2.6** `domain/synch.GenerateSyncID` — port [sync_fio_to_sheets.py](scripts/sync_fio_to_sheets.py) `generate_sync_id` (SHA-256, byte-stable hash; verify float string format against real sheet rows)
 - [ ] **M2.7** `domain/matching.BuildNameVariants` + `MatchMembers` — port `_build_name_variants` and `match_members` from [match_payments.py](scripts/match_payments.py) (auto vs review confidence, common-surname filter)
--- a/docs/plans/2026-05-05-2144-branch-per-feature-workflow.md
+++ b/docs/plans/2026-05-05-2144-branch-per-feature-workflow.md
@@ -0,0 +1,83 @@
+# Branch-per-feature + Gitea MR workflow
+
+## Context
+
+Until now, Claude has been committing feature work directly to `main`
+(see recent history: `feat: Lower adult monthly fee…`, `feat: Go rewrite M1…`,
+all on `main`). The user wants to switch to a branch-per-feature flow with
+review via a Gitea merge request, so that:
+
+- Feature work is reviewable as a self-contained diff before it lands.
+- `main` stays releasable.
+- The change history shows reviewed merges, not unsupervised pushes.
+
+The remote is Gitea (`https://gitea.home.hrajfrisbee.cz/kacerr/fuj-management.git`),
+which supports the standard pull/merge-request flow.
+
+This plan only modifies `CLAUDE.md`. No code changes.
+
+## Scope clarification (from user)
+
+- **MR creation method:** Claude pushes the branch and prints the Gitea
+  "compare" URL. The user opens / merges the MR in the browser. No `tea` CLI,
+  no API calls.
+- **When the flow applies:** Features only. Small bug fixes and hotfixes can
+  still be committed straight to `main`. Claude decides feature-vs-fix based
+  on scope; when uncertain, ask.
+- **Branch naming:** `feat/<slug>` for features, `fix/<slug>` for the
+  occasional bug-fix branch the user explicitly requests. `<slug>` is
+  kebab-case, short, descriptive.
+
+## Change
+
+Add a new top-level section to `CLAUDE.md` titled **"Branching & merge requests"**,
+placed immediately before the existing `## Git Commits` section so the workflow
+context appears before the commit-message convention.
+
+### Proposed section content
+
+```markdown
+## Branching & merge requests
+
+The remote is Gitea (`gitea.home.hrajfrisbee.cz/kacerr/fuj-management`).
+For **features**, do not commit to `main` directly. Use a branch + merge
+request flow:
+
+1. **Create a branch off `main`** before starting work:
+   - `feat/<slug>` for features (e.g. `feat/qr-code-overlay`)
+   - `fix/<slug>` for bug-fix branches the user explicitly asks for
+   - `<slug>` is short kebab-case
+2. **Commit on the branch** following the existing commit conventions
+   (Co-Authored-By trailer, etc.).
+3. **Push the branch** to `origin` with `-u` so it tracks.
+4. **Print the Gitea compare URL** so the user can open the MR in the
+   browser:
+   `https://gitea.home.hrajfrisbee.cz/kacerr/fuj-management/compare/main...<branch>`
+   Do **not** use `tea`, `gh`, or call the Gitea API — the user opens and
+   merges the MR themselves.
+5. **Do not merge or delete the branch** from the CLI. The user does that
+   in Gitea.
+
+**Exceptions — when committing straight to `main` is fine:**
+- Small bug fixes / hotfixes the user describes as such.
+- Typo / comment / formatting tweaks.
+- Edits the user explicitly says to push to `main`.
+
+When uncertain whether something is "feature" or "small fix", ask before
+committing.
+```
+
+## Files to modify
+
+- [CLAUDE.md](CLAUDE.md) — insert the new `## Branching & merge requests`
+  section just above the existing `## Git Commits` section (around line 95).
+
+## Verification
+
+- Re-read `CLAUDE.md` and confirm the new section is well-placed and the
+  existing structure (`## Git Commits`, `## Changelog`, `## Plans`) is intact.
+- `git diff CLAUDE.md` should show only an additive change.
+- No code, tests, or runtime behavior changes — nothing else to test.
+- Behavior verification happens on the **next** feature request: Claude
+  should create a `feat/<slug>` branch, commit there, push, and print the
+  compare URL instead of committing on `main`.
--- a/docs/plans/2026-05-05-2204-go-rewrite-m2-1-czech-normalize.md
+++ b/docs/plans/2026-05-05-2204-go-rewrite-m2-1-czech-normalize.md
@@ -0,0 +1,154 @@
+# Plan: Go rewrite — M2.1 `domain/czech.Normalize`
+
+## Context
+
+The Go rewrite finished M1 (skeleton, tooling, hello server) in commit
+`cf0f176` on 2026-05-04. The next milestone, **M2 — Pure-domain helpers**,
+is current per [progress tracker](2026-05-03-2349-go-backend-rewrite-progress.md)
+but has no work landed yet (all 12 sub-tasks unchecked).
+
+This plan covers only the **first** M2 task: porting Python's
+`normalize` from [scripts/czech_utils.py](../../scripts/czech_utils.py)
+to Go as `internal/domain/czech.Normalize`. It is the lowest-level helper
+in the domain — `parse_month_references`, `_build_name_variants`,
+`match_members`, exception keys, and `reconcile` all transitively depend
+on it. Getting it byte-equivalent first removes a class of "why does my
+match not fire" failures from every later M2 task.
+
+**Decision (confirmed in plan-mode Q):** start with hand-written Go unit
+tests for fresh Czech edge cases. Defer parity-fixture wiring until
+M3.1/M3.2 land (separate task); add the parity test for `Normalize`
+retroactively at that point.
+
+## Scope
+
+- New package `go/internal/domain/czech/` with `Normalize` and unit tests.
+- Add `golang.org/x/text` dependency to `go/go.mod` (currently zero deps).
+- **Out of scope:** `ParseMonthReferences` (M2.2), fixture tooling
+  (M3.1/M3.2), CLI subcommand wiring (M2.11/M2.12), parity test runner.
+
+## Recommended approach
+
+### Python contract to match
+
+```python
+def normalize(text: str) -> str:
+    nfkd = unicodedata.normalize("NFKD", text)
+    return "".join(c for c in nfkd if not unicodedata.combining(c)).lower()
+```
+
+Three semantic operations:
+1. NFKD decompose
+2. Drop characters where `unicodedata.combining(c)` is non-zero
+3. Lowercase
+
+### Go implementation
+
+`go/internal/domain/czech/normalize.go`:
+
+```go
+package czech
+
+import (
+    "strings"
+    "unicode"
+    "golang.org/x/text/unicode/norm"
+)
+
+func Normalize(s string) string {
+    decomposed := norm.NFKD.String(s)
+    var b strings.Builder
+    b.Grow(len(decomposed))
+    for _, r := range decomposed {
+        if unicode.In(r, unicode.Mn) {
+            continue
+        }
+        b.WriteRune(r)
+    }
+    return strings.ToLower(b.String())
+}
+```
+
+**Two precision points worth flagging:**
+
+1. **`unicode.Mn` not `unicode.IsMark`.** The plan's library-choices
+   table mentions `unicode.IsMark`, but that covers Mn + Mc + Me. Python
+   `unicodedata.combining()` returns 0 for Mc/Me (their canonical
+   combining class is 0), so it effectively filters only Mn. Use
+   `unicode.In(r, unicode.Mn)` for byte-equivalence with Python. Cite
+   this in a one-line code comment; it's the kind of thing a future
+   reader will second-guess.
+2. **`strings.ToLower` vs Go's locale-aware tools.** Python's `.lower()`
+   on already-decomposed Latin is straight ASCII lowercase for Czech.
+   Stdlib `strings.ToLower` matches; do not pull in `golang.org/x/text/cases`.
+
+### Tests
+
+`go/internal/domain/czech/normalize_test.go` — table-driven, covers:
+
+- ASCII passthrough: `"Honza" → "honza"`
+- Czech lowercase diacritics: `"žluťoučký" → "zlutoucky"`
+- Mixed case + diacritics: `"Příliš" → "prilis"`
+- Czech caron + ring: `"Dvořák" → "dvorak"`, `"Růžena" → "ruzena"`
+- Hard letters: `"Čeněk" → "cenek"`, `"Kačer" → "kacer"`
+- Empty string: `"" → ""`
+- Already-normalized: `"prilis" → "prilis"` (idempotence)
+- Pre-composed vs decomposed input both produce the same output (NFC
+  `"é"` and `"é"` both → `"e"`)
+- Whitespace preserved: `"Jan Novák" → "jan novak"`
+
+Run a one-shot cross-check against the live Python implementation for
+each test input before locking the table:
+```
+PYTHONPATH=scripts:. python -c \
+  'from czech_utils import normalize; print(repr(normalize("Dvořák")))'
+```
+This is the manual stand-in for the M3 parity fixtures.
+
+### Wire-up
+
+- `go get golang.org/x/text@latest` (run from `go/`); `go mod tidy`.
+- No CLI changes — `cmd/fuj` already stubs `fees`/`reconcile` with
+  exit code 2; no need to touch dispatcher for this task. `Normalize`
+  is consumed by other domain code, not by users directly.
+
+## Critical files
+
+- New: [go/internal/domain/czech/normalize.go](../../go/internal/domain/czech/normalize.go)
+- New: [go/internal/domain/czech/normalize_test.go](../../go/internal/domain/czech/normalize_test.go)
+- Modified: [go/go.mod](../../go/go.mod), `go/go.sum` (new)
+- Reference (read-only): [scripts/czech_utils.py](../../scripts/czech_utils.py) — the porting source
+- Reference (read-only): [docs/plans/2026-05-03-2349-go-backend-rewrite.md](2026-05-03-2349-go-backend-rewrite.md) — risk #3 (NFKD edge cases)
+
+## Verification
+
+End-to-end checks before marking M2.1 done:
+
+1. `cd go && go build ./...` — clean compile.
+2. `cd go && go test ./internal/domain/czech/...` — all table cases green.
+3. `cd go && go test -race ./...` — race-clean.
+4. `cd go && golangci-lint run` (or `make go-lint` from repo root) — clean.
+5. **Spot parity** (manual, will be automated in M3): for each Go test
+   input, run the Python `normalize` via `PYTHONPATH=scripts:. python -c
+   '...'` and confirm bytes match. Capture the diff in the commit
+   message if anything surprises.
+6. `make go-build && make go-test && make go-lint` from repo root — proves
+   the existing M1 gate still passes.
+
+## Branching & follow-up
+
+Per [CLAUDE.md](../../CLAUDE.md), this is feature work → branch + Gitea MR:
+
+- Branch: `feat/m2-1-czech-normalize` off `main`.
+- Single commit, Co-Authored-By trailer.
+- Push with `-u`, print compare URL
+  `https://gitea.home.hrajfrisbee.cz/kacerr/fuj-management/compare/main...feat/m2-1-czech-normalize`
+- User opens/merges the MR.
+- After merge: tick `M2.1` in the progress tracker with the commit SHA;
+  add a one-line CHANGELOG entry; record any porting surprise in the
+  tracker's "Notes & decisions" section (e.g. the `Mn`-vs-`IsMark`
+  precision point if it bears noting).
+
+Next task after this lands is **M2.2 `ParseMonthReferences`** — the
+larger, edge-case-heavier sibling. Whether to start it before or after
+M3.1/M3.2 is a separate decision the user can make then.
--- a/docs/plans/2026-05-05-2337-go-rewrite-m2-2-parse-month-references.md
+++ b/docs/plans/2026-05-05-2337-go-rewrite-m2-2-parse-month-references.md
@@ -0,0 +1,205 @@
+# Plan: Go rewrite — M2.2 `domain/czech.ParseMonthReferences`
+
+## Context
+
+M2.1 (`domain/czech.Normalize`) merged via PR #4 (`d9a61b3`) on
+2026-05-05. Per the [progress tracker](2026-05-03-2349-go-backend-rewrite-progress.md),
+**M2.2** is next: port `parse_month_references` from
+[scripts/czech_utils.py](../../scripts/czech_utils.py) to Go as
+`internal/domain/czech.ParseMonthReferences`.
+
+This function is the second-most-load-bearing pure helper after
+`reconcile`: every payment-message → month inference goes through it.
+Risk #4 in the [parent plan](2026-05-03-2349-go-backend-rewrite.md)
+specifically calls out its semantics — wrap-around year inference and
+the `m >= 10 → previous year` standalone heuristic — as easy to mis-port.
+
+This plan locks the test table against the live Python implementation
+*before* coding, so the Go port has a verified parity baseline even
+before the M3.1/M3.2 fixture infrastructure exists.
+
+## Scope
+
+- New file `go/internal/domain/czech/parse_month_references.go` in the
+  existing `czech` package (alongside [normalize.go](../../go/internal/domain/czech/normalize.go)).
+- New file `go/internal/domain/czech/parse_month_references_test.go`
+  with the test table below.
+- **Out of scope:** parity-fixture wiring (M3.1/M3.2); CLI hook-up
+  (M2.11/M2.12); any consumer call-sites.
+- **No new dependencies** — stdlib `regexp`, `sort`, `strconv`, `strings`
+  plus the existing `czech.Normalize` cover everything.
+
+## Recommended approach
+
+### Python contract to mirror
+
+Three regex passes, all run on `normalize(text)`:
+
+1. `([\d+]+)\s*/\s*(\d{2,4})` — captures `"11+12/2025"`, `"01/26"`, `"1/26"`.
+   Split the months part on `+`, keep digit-only tokens, validate `1..12`.
+   Year < 100 → year + 2000.
+2. `(\d{1,2})\s*\.\s*(\d{4})` — captures `"12.2025"`. **4-digit year only**
+   (so `"1.26"` does not match).
+3. Czech month names. First the **range** sub-pass:
+   `(name)\s*-\s*(name)` finds pairs; walk start→end with `m % 12 + 1`,
+   stopping when `m == end_m`. Wrap rule: if `start_m > end_m`, months
+   `>= start_m` are `defaultYear - 1`, the rest are `defaultYear`. Both
+   matched names go into a `foundInRanges` set.
+   Then the **standalone** sub-pass: `\b(name)\b`, skipping any name in
+   `foundInRanges`. For each remaining match, `m >= 10 → defaultYear - 1`,
+   else `defaultYear`.
+
+Output: sorted, deduplicated `[]string` of `"YYYY-MM"`.
+
+### Go signature
+
+```go
+package czech
+
+// ParseMonthReferences extracts YYYY-MM month references from Czech
+// free text. defaultYear seeds two heuristics: standalone month names
+// with m >= 10 are treated as defaultYear-1 (out-of-year backfill), and
+// wrap-around ranges (e.g. listopad-leden) place months >= start in
+// defaultYear-1.
+func ParseMonthReferences(text string, defaultYear int) []string
+```
+
+Required `defaultYear` (no default value — Go convention).
+
+### Implementation sketch
+
+```go
+var czechMonths = map[string]int{
+    "leden": 1, "ledna": 1, "lednu": 1,
+    "unor": 2, "unora": 2, "unoru": 2,
+    "brezen": 3, "brezna": 3, "breznu": 3,
+    "duben": 4, "dubna": 4, "dubnu": 4,
+    "kveten": 5, "kvetna": 5, "kvetnu": 5,
+    "cerven": 6, "cervna": 6, "cervnu": 6,
+    "cervenec": 7, "cervnce": 7, "cervenci": 7,
+    "srpen": 8, "srpna": 8, "srpnu": 8,
+    "zari": 9,
+    "rijen": 10, "rijna": 10, "rijnu": 10,
+    "listopad": 11, "listopadu": 11,
+    "prosinec": 12, "prosince": 12, "prosinci": 12,
+}
+
+// Sorted by descending length at init, so longer alternatives win in
+// the regex (e.g. "cervenec" beats "cerven"). Mirrors Python's
+// sorted(..., key=len, reverse=True).
+var monthNameAlt = buildMonthNameAlt()
+
+var (
+    numericRe = regexp.MustCompile(`([\d+]+)\s*/\s*(\d{2,4})`)
+    dotRe     = regexp.MustCompile(`(\d{1,2})\s*\.\s*(\d{4})`)
+    rangeRe   = regexp.MustCompile(`(` + monthNameAlt + `)\s*-\s*(` + monthNameAlt + `)`)
+    standRe   = regexp.MustCompile(`\b(` + monthNameAlt + `)\b`)
+)
+```
+
+Three Go-specific gotchas worth a code comment:
+
+1. **RE2 alternation is leftmost-first**, same as Python `re`. Sorting
+   month names by descending length is therefore necessary (otherwise
+   `"cervenec"` matches as `"cerven"` + leftover `"ec"`). Mirror the
+   Python sort exactly.
+2. **Map iteration is randomized in Go.** Build the alternation list
+   from a sorted slice of keys, not by iterating the map.
+3. **`\d` and `\b`** in Go RE2 are ASCII-only, which matches the
+   effective behavior on `Normalize`'d input (NFKD already collapsed
+   any Unicode digits/letters that would matter; standalone Devanagari
+   digits in member messages aren't a real-world concern).
+
+The walk loop uses a bounded counter (max 12 iterations) defensively in
+Go; Python's `while True` is fine because every range terminates within
+12 hops, but a future reader appreciates the bound.
+
+### Test table (verified against live Python — `default_year=2026`)
+
+Locked outputs from `PYTHONPATH=scripts:. python -c 'from czech_utils
+import parse_month_references; print(parse_month_references(<input>, 2026))'`
+on 2026-05-05.
+
+| # | Input | Expected | Path exercised |
+|---|---|---|---|
+| 1 | `""` | `[]` | empty |
+| 2 | `"11+12/2025"` | `["2025-11", "2025-12"]` | numeric, plus-split |
+| 3 | `"1/2026"` | `["2026-01"]` | numeric, single |
+| 4 | `"01/26"` | `["2026-01"]` | 2-digit year normalization |
+| 5 | `"11+12/25"` | `["2025-11", "2025-12"]` | plus-split + 2-digit year |
+| 6 | `"12+1+2/2026"` | `["2026-01", "2026-02", "2026-12"]` | sorting |
+| 7 | `"12.2025"` | `["2025-12"]` | dot pattern |
+| 8 | `"1.26"` | `[]` | dot pattern requires 4-digit year |
+| 9 | `"leden"` | `["2026-01"]` | standalone, m<10 |
+| 10 | `"prosinec"` | `["2025-12"]` | standalone, m≥10 → previous year |
+| 11 | `"prosince"` | `["2025-12"]` | declension |
+| 12 | `"lednu"` | `["2026-01"]` | declension |
+| 13 | `"rijen"` | `["2025-10"]` | m≥10 boundary (10 itself) |
+| 14 | `"zari"` | `["2026-09"]` | m<10 just below boundary |
+| 15 | `"listopad-leden"` | `["2025-11", "2025-12", "2026-01"]` | wrap range Nov→Jan |
+| 16 | `"rijen-leden"` | `["2025-10", "2025-11", "2025-12", "2026-01"]` | wrap from October |
+| 17 | `"unor-kveten"` | `["2026-02", "2026-03", "2026-04", "2026-05"]` | non-wrap range |
+| 18 | `"leden-leden"` | `["2026-01"]` | degenerate range |
+| 19 | `"unor-listopad"` | `["2026-02", ..., "2026-11"]` (10 entries) | range spans m≥10 — heuristic does NOT fire (range exclusion) |
+| 20 | `"cervenec-srpen"` | `["2026-07", "2026-08"]` | longest-match alt (`cervenec` not `cerven`+`ec`) |
+| 21 | `"listopad-leden, prosinec"` | `["2025-11", "2025-12", "2026-01"]` | range + standalone, dedup |
+| 22 | `"prosinec leden"` | `["2025-12", "2026-01"]` | two standalones, no range |
+| 23 | `"11+12/2025, leden-brezen"` | `["2025-11", "2025-12", "2026-01", "2026-02", "2026-03"]` | numeric + range mix |
+| 24 | `"11+12/25 a listopad"` | `["2025-11", "2025-12"]` | dedup across passes |
+| 25 | `"prosince/2025"` | `["2025-12"]` | numeric pattern fails (no digits before `/`); standalone fires |
+| 26 | `"listopad-prosinec/2025"` | `["2026-11", "2026-12"]` | range wins; numeric pattern fails |
+| 27 | `"01.2026 / 02.2026"` | `["2026-01", "2026-02"]` | dot pattern only; numeric matches `(2026, 02)` but month 2026 is out of range |
+| 28 | `"/12/2025"` | `["2025-12"]` | numeric matches at second `/` |
+| 29 | `"PROSINEC"` | `["2025-12"]` | normalize lowercases |
+| 30 | `"Žluťoučký prosinec"` | `["2025-12"]` | normalize strips diacritics |
+| 31 | `"Únor - květen"` | `["2026-02", ..., "2026-05"]` | range tolerates spaces around `-`, diacritics survive normalize |
+| 32 | `"platba 11/2025 a leden"` | `["2025-11", "2026-01"]` | mixed natural-language |
+| 33 | `"December"` | `[]` | English month names not recognized |
+| 34 | `"11+12/2025 11+12/2025"` | `["2025-11", "2025-12"]` | dedup of repeated input |
+| 35 | `"leden 2026"` | `["2026-01"]` | trailing year is ignored unless dot/slash separator present |
+
+35 cases is enough to lock semantics; the M3.x corpus will pile on
+real-message fixtures later.
+
+### Wire-up
+
+- No `go.mod` changes (stdlib only).
+- No CLI changes.
+- `Normalize` is in the same package, so call it directly.
+
+## Critical files
+
+- New: [go/internal/domain/czech/parse_month_references.go](../../go/internal/domain/czech/parse_month_references.go)
+- New: [go/internal/domain/czech/parse_month_references_test.go](../../go/internal/domain/czech/parse_month_references_test.go)
+- Reference (read-only): [scripts/czech_utils.py](../../scripts/czech_utils.py) — the porting source
+- Reference (read-only): [docs/plans/2026-05-03-2349-go-backend-rewrite.md](2026-05-03-2349-go-backend-rewrite.md) — risk #4
+- Reuses: [go/internal/domain/czech/normalize.go](../../go/internal/domain/czech/normalize.go) — `Normalize` is called once at the top of `ParseMonthReferences`
+
+## Verification
+
+End-to-end checks before marking M2.2 done:
+
+1. `cd go && go build ./...` — clean compile.
+2. `cd go && go test ./internal/domain/czech/...` — all 35 table cases green.
+3. `cd go && go test -race ./...` — race-clean (regex compiles are global; verify no init races).
+4. `cd go && golangci-lint run` (or `make go-lint` from repo root) — clean, gofumpt-formatted.
+5. **Spot parity** (manual, will be automated in M3.x): each test input has its expected output captured from the live Python implementation on 2026-05-05; the test table itself is the parity record. If any case diverges during implementation, re-run Python with the exact input to confirm the truth and update either the Go code or the test entry.
+6. `make go-build && make go-test && make go-lint` from repo root — proves M1/M2.1 gate still passes.
+
+## Branching & follow-up
+
+Per [CLAUDE.md](../../CLAUDE.md), this is feature work → branch + Gitea MR via `tea`:
+
+- Branch: `feat/m2-2-parse-month-references` off `main`.
+- Single focused commit, Co-Authored-By trailer.
+- Push with `-u`.
+- Open MR with `tea pr create --title "feat(go/M2.2): port czech.ParseMonthReferences" --description ... --base main --head feat/m2-2-parse-month-references`. Print the MR URL for the user.
+- User merges/deletes the branch in Gitea — never from the CLI.
+
+After merge (small doc edits land straight on `main` per CLAUDE.md exception):
+
+- Tick `M2.2` in the [progress tracker](2026-05-03-2349-go-backend-rewrite-progress.md) with the merge SHA.
+- Add a one-line `CHANGELOG.md` entry (timestamp via `date "+%Y-%m-%d %H:%M %Z"`).
+- Record any porting surprise (e.g. an unexpected diff between Go RE2 and Python `re`) in the tracker's "Notes & decisions" section.
+
+Next task is **M2.3 `domain/fees.CalculateFee`** — straightforward constants table; no parser semantics to debate.
--- a/go/go.mod
+++ b/go/go.mod
@@ -1,3 +1,5 @@
 module fuj-management/go

 go 1.26.1
+
+require golang.org/x/text v0.36.0
--- a/go/go.sum
+++ b/go/go.sum
@@ -0,0 +1,2 @@
+golang.org/x/text v0.36.0 h1:JfKh3XmcRPqZPKevfXVpI1wXPTqbkE5f7JA92a55Yxg=
+golang.org/x/text v0.36.0/go.mod h1:NIdBknypM8iqVmPiuco0Dh6P5Jcdk8lJL0CUebqK164=
--- a/go/internal/domain/czech/normalize.go
+++ b/go/internal/domain/czech/normalize.go
@@ -0,0 +1,26 @@
+package czech
+
+import (
+	"strings"
+	"unicode"
+
+	"golang.org/x/text/unicode/norm"
+)
+
+// Normalize strips diacritics and lowercases s.
+//
+// Matches Python: unicodedata.normalize("NFKD", s) then filter out
+// combining characters (unicode.Mn only — not Mc/Me, which have
+// combining class 0 in Python's unicodedata.combining()).
+func Normalize(s string) string {
+	decomposed := norm.NFKD.String(s)
+	var b strings.Builder
+	b.Grow(len(decomposed))
+	for _, r := range decomposed {
+		if unicode.In(r, unicode.Mn) {
+			continue
+		}
+		b.WriteRune(r)
+	}
+	return strings.ToLower(b.String())
+}
--- a/go/internal/domain/czech/normalize_test.go
+++ b/go/internal/domain/czech/normalize_test.go
@@ -0,0 +1,31 @@
+package czech
+
+import "testing"
+
+func TestNormalize(t *testing.T) {
+	cases := []struct {
+		in   string
+		want string
+	}{
+		{"Honza", "honza"},
+		{"žluťoučký", "zlutoucky"},
+		{"Příliš", "prilis"},
+		{"Dvořák", "dvorak"},
+		{"Růžena", "ruzena"},
+		{"Čeněk", "cenek"},
+		{"Kačer", "kacer"},
+		{"", ""},
+		{"prilis", "prilis"},                     // idempotent
+		{"Jan Novák", "jan novak"},               // whitespace preserved
+		{"é", "e"},                               // precomposed é (NFC)
+		{"é", "e"},                              // decomposed e + combining acute
+		{"Ondřej Procházka", "ondrej prochazka"}, // realistic full name
+	}
+
+	for _, tc := range cases {
+		got := Normalize(tc.in)
+		if got != tc.want {
+			t.Errorf("Normalize(%q) = %q, want %q", tc.in, got, tc.want)
+		}
+	}
+}
--- a/go/internal/domain/czech/parse_month_references.go
+++ b/go/internal/domain/czech/parse_month_references.go
@@ -0,0 +1,154 @@
+package czech
+
+import (
+	"fmt"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+var czechMonths = map[string]int{
+	"leden": 1, "ledna": 1, "lednu": 1,
+	"unor": 2, "unora": 2, "unoru": 2,
+	"brezen": 3, "brezna": 3, "breznu": 3,
+	"duben": 4, "dubna": 4, "dubnu": 4,
+	"kveten": 5, "kvetna": 5, "kvetnu": 5,
+	"cerven": 6, "cervna": 6, "cervnu": 6,
+	"cervenec": 7, "cervnce": 7, "cervenci": 7,
+	"srpen": 8, "srpna": 8, "srpnu": 8,
+	"zari":  9,
+	"rijen": 10, "rijna": 10, "rijnu": 10,
+	"listopad": 11, "listopadu": 11,
+	"prosinec": 12, "prosince": 12, "prosinci": 12,
+}
+
+var (
+	numericRe *regexp.Regexp
+	dotRe     *regexp.Regexp
+	rangeRe   *regexp.Regexp
+	standRe   *regexp.Regexp
+)
+
+func init() {
+	// Sort by descending length so longer alternatives win in RE2 leftmost-first
+	// matching (e.g. "cervenec" is tried before "cerven").
+	names := make([]string, 0, len(czechMonths))
+	for name := range czechMonths {
+		names = append(names, name)
+	}
+	sort.Slice(names, func(i, j int) bool {
+		if len(names[i]) != len(names[j]) {
+			return len(names[i]) > len(names[j])
+		}
+		return names[i] < names[j]
+	})
+	alt := strings.Join(names, "|")
+
+	numericRe = regexp.MustCompile(`([\d+]+)\s*/\s*(\d{2,4})`)
+	dotRe = regexp.MustCompile(`(\d{1,2})\s*\.\s*(\d{4})`)
+	rangeRe = regexp.MustCompile(`(` + alt + `)\s*-\s*(` + alt + `)`)
+	standRe = regexp.MustCompile(`\b(` + alt + `)\b`)
+}
+
+// ParseMonthReferences extracts YYYY-MM month references from Czech free text.
+//
+// defaultYear seeds two heuristics: standalone month names with m >= 10 are
+// treated as defaultYear-1 (out-of-year backfill), and wrap-around ranges
+// (e.g. listopad-leden) place months >= start_m in defaultYear-1.
+//
+// Returns a sorted, deduplicated slice of "YYYY-MM" strings.
+func ParseMonthReferences(text string, defaultYear int) []string {
+	normalized := Normalize(text)
+	seen := map[string]struct{}{}
+
+	add := func(year, m int) {
+		if m >= 1 && m <= 12 {
+			seen[fmt.Sprintf("%04d-%02d", year, m)] = struct{}{}
+		}
+	}
+
+	// Pass 1: numeric months — "11+12/2025", "01/26", "1/2026"
+	for _, groups := range numericRe.FindAllStringSubmatch(normalized, -1) {
+		monthsPart, yearStr := groups[1], groups[2]
+		year, err := strconv.Atoi(yearStr)
+		if err != nil {
+			continue
+		}
+		if year < 100 {
+			year += 2000
+		}
+		for mStr := range strings.SplitSeq(monthsPart, "+") {
+			mStr = strings.TrimSpace(mStr)
+			if mStr == "" {
+				continue
+			}
+			allDigits := true
+			for _, c := range mStr {
+				if c < '0' || c > '9' {
+					allDigits = false
+					break
+				}
+			}
+			if !allDigits {
+				continue
+			}
+			m, err := strconv.Atoi(mStr)
+			if err != nil {
+				continue
+			}
+			add(year, m)
+		}
+	}
+
+	// Pass 2: dot-separated month.year — "12.2025" (4-digit year only)
+	for _, groups := range dotRe.FindAllStringSubmatch(normalized, -1) {
+		m, _ := strconv.Atoi(groups[1])
+		year, _ := strconv.Atoi(groups[2])
+		add(year, m)
+	}
+
+	// Pass 3a: Czech month name ranges — "listopad-leden"
+	foundInRanges := map[string]struct{}{}
+	for _, groups := range rangeRe.FindAllStringSubmatch(normalized, -1) {
+		startName, endName := groups[1], groups[2]
+		foundInRanges[startName] = struct{}{}
+		foundInRanges[endName] = struct{}{}
+		startM := czechMonths[startName]
+		endM := czechMonths[endName]
+		wraps := startM > endM
+		m := startM
+		for range 12 {
+			year := defaultYear
+			if wraps && m >= startM {
+				year = defaultYear - 1
+			}
+			add(year, m)
+			if m == endM {
+				break
+			}
+			m = m%12 + 1
+		}
+	}
+
+	// Pass 3b: standalone Czech month names (not part of a range)
+	for _, groups := range standRe.FindAllStringSubmatch(normalized, -1) {
+		name := groups[1]
+		if _, inRange := foundInRanges[name]; inRange {
+			continue
+		}
+		m := czechMonths[name]
+		year := defaultYear
+		if m >= 10 {
+			year = defaultYear - 1
+		}
+		add(year, m)
+	}
+
+	result := make([]string, 0, len(seen))
+	for k := range seen {
+		result = append(result, k)
+	}
+	sort.Strings(result)
+	return result
+}
--- a/go/internal/domain/czech/parse_month_references_test.go
+++ b/go/internal/domain/czech/parse_month_references_test.go
@@ -0,0 +1,244 @@
+package czech
+
+import (
+	"reflect"
+	"testing"
+)
+
+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))'
+	tests := []struct {
+		name        string
+		input       string
+		defaultYear int
+		want        []string
+	}{
+		{
+			name:        "empty",
+			input:       "",
+			defaultYear: 2026,
+			want:        []string{},
+		},
+		{
+			name:        "numeric plus-split two months full year",
+			input:       "11+12/2025",
+			defaultYear: 2026,
+			want:        []string{"2025-11", "2025-12"},
+		},
+		{
+			name:        "numeric single month full year",
+			input:       "1/2026",
+			defaultYear: 2026,
+			want:        []string{"2026-01"},
+		},
+		{
+			name:        "numeric 2-digit year",
+			input:       "01/26",
+			defaultYear: 2026,
+			want:        []string{"2026-01"},
+		},
+		{
+			name:        "numeric plus-split with 2-digit year",
+			input:       "11+12/25",
+			defaultYear: 2026,
+			want:        []string{"2025-11", "2025-12"},
+		},
+		{
+			name:        "numeric three months sorted",
+			input:       "12+1+2/2026",
+			defaultYear: 2026,
+			want:        []string{"2026-01", "2026-02", "2026-12"},
+		},
+		{
+			name:        "dot pattern",
+			input:       "12.2025",
+			defaultYear: 2026,
+			want:        []string{"2025-12"},
+		},
+		{
+			name:        "dot pattern requires 4-digit year",
+			input:       "1.26",
+			defaultYear: 2026,
+			want:        []string{},
+		},
+		{
+			name:        "standalone month below m10 threshold",
+			input:       "leden",
+			defaultYear: 2026,
+			want:        []string{"2026-01"},
+		},
+		{
+			name:        "standalone month m10 heuristic",
+			input:       "prosinec",
+			defaultYear: 2026,
+			want:        []string{"2025-12"},
+		},
+		{
+			name:        "declension prosince",
+			input:       "prosince",
+			defaultYear: 2026,
+			want:        []string{"2025-12"},
+		},
+		{
+			name:        "declension lednu",
+			input:       "lednu",
+			defaultYear: 2026,
+			want:        []string{"2026-01"},
+		},
+		{
+			name:        "standalone m10 boundary (rijen = October)",
+			input:       "rijen",
+			defaultYear: 2026,
+			want:        []string{"2025-10"},
+		},
+		{
+			name:        "standalone m9 just below boundary (zari = September)",
+			input:       "zari",
+			defaultYear: 2026,
+			want:        []string{"2026-09"},
+		},
+		{
+			name:        "range wrap Nov-Jan",
+			input:       "listopad-leden",
+			defaultYear: 2026,
+			want:        []string{"2025-11", "2025-12", "2026-01"},
+		},
+		{
+			name:        "range wrap starting at October",
+			input:       "rijen-leden",
+			defaultYear: 2026,
+			want:        []string{"2025-10", "2025-11", "2025-12", "2026-01"},
+		},
+		{
+			name:        "range no wrap",
+			input:       "unor-kveten",
+			defaultYear: 2026,
+			want:        []string{"2026-02", "2026-03", "2026-04", "2026-05"},
+		},
+		{
+			name:        "degenerate range same month",
+			input:       "leden-leden",
+			defaultYear: 2026,
+			want:        []string{"2026-01"},
+		},
+		{
+			name:        "range spanning m10 — heuristic does NOT fire for range members",
+			input:       "unor-listopad",
+			defaultYear: 2026,
+			want:        []string{"2026-02", "2026-03", "2026-04", "2026-05", "2026-06", "2026-07", "2026-08", "2026-09", "2026-10", "2026-11"},
+		},
+		{
+			name:        "longest-match alternation cervenec beats cerven",
+			input:       "cervenec-srpen",
+			defaultYear: 2026,
+			want:        []string{"2026-07", "2026-08"},
+		},
+		{
+			name:        "range plus standalone — range excludes, dedup",
+			input:       "listopad-leden, prosinec",
+			defaultYear: 2026,
+			want:        []string{"2025-11", "2025-12", "2026-01"},
+		},
+		{
+			name:        "two standalones no range",
+			input:       "prosinec leden",
+			defaultYear: 2026,
+			want:        []string{"2025-12", "2026-01"},
+		},
+		{
+			name:        "numeric plus range mix",
+			input:       "11+12/2025, leden-brezen",
+			defaultYear: 2026,
+			want:        []string{"2025-11", "2025-12", "2026-01", "2026-02", "2026-03"},
+		},
+		{
+			name:        "dedup across numeric and standalone passes",
+			input:       "11+12/25 a listopad",
+			defaultYear: 2026,
+			want:        []string{"2025-11", "2025-12"},
+		},
+		{
+			name:        "no digits before slash — standalone fires instead",
+			input:       "prosince/2025",
+			defaultYear: 2026,
+			want:        []string{"2025-12"},
+		},
+		{
+			name:        "range with trailing slash-year — numeric fails, range wins",
+			input:       "listopad-prosinec/2025",
+			defaultYear: 2026,
+			want:        []string{"2026-11", "2026-12"},
+		},
+		{
+			name:        "dot pattern only — numeric matches but month out of 1-12 range",
+			input:       "01.2026 / 02.2026",
+			defaultYear: 2026,
+			want:        []string{"2026-01", "2026-02"},
+		},
+		{
+			name:        "leading slash — numeric matches at second slash",
+			input:       "/12/2025",
+			defaultYear: 2026,
+			want:        []string{"2025-12"},
+		},
+		{
+			name:        "uppercase input normalized",
+			input:       "PROSINEC",
+			defaultYear: 2026,
+			want:        []string{"2025-12"},
+		},
+		{
+			name:        "diacritics stripped by Normalize",
+			input:       "Žluťoučký prosinec",
+			defaultYear: 2026,
+			want:        []string{"2025-12"},
+		},
+		{
+			name:        "diacritics in range with spaces around dash",
+			input:       "Únor - květen",
+			defaultYear: 2026,
+			want:        []string{"2026-02", "2026-03", "2026-04", "2026-05"},
+		},
+		{
+			name:        "natural language mixed with numeric and standalone",
+			input:       "platba 11/2025 a leden",
+			defaultYear: 2026,
+			want:        []string{"2025-11", "2026-01"},
+		},
+		{
+			name:        "English month name not recognized",
+			input:       "December",
+			defaultYear: 2026,
+			want:        []string{},
+		},
+		{
+			name:        "duplicate input deduped",
+			input:       "11+12/2025 11+12/2025",
+			defaultYear: 2026,
+			want:        []string{"2025-11", "2025-12"},
+		},
+		{
+			name:        "trailing year without separator ignored",
+			input:       "leden 2026",
+			defaultYear: 2026,
+			want:        []string{"2026-01"},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			got := ParseMonthReferences(tc.input, tc.defaultYear)
+			if got == nil {
+				got = []string{}
+			}
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("ParseMonthReferences(%q, %d)\n  got  %v\n  want %v",
+					tc.input, tc.defaultYear, got, tc.want)
+			}
+		})
+	}
+}
--- a/go/internal/domain/fees/fees.go
+++ b/go/internal/domain/fees/fees.go
@@ -0,0 +1,34 @@
+// Package fees ports fee calculation from scripts/attendance.py.
+package fees
+
+const (
+	AdultFeeDefault = 700 // CZK fallback for 2+ practices when month not in AdultFeeMonthlyRate
+	AdultFeeSingle  = 200 // CZK for exactly 1 practice
+)
+
+// AdultFeeMonthlyRate mirrors ADULT_FEE_MONTHLY_RATE in 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,
+	"2026-01": 750, "2026-02": 750, "2026-03": 350,
+	"2026-04": 700, "2026-05": 700,
+}
+
+// CalculateFee returns the adult fee in CZK for attendanceCount practices in
+// the given monthKey (format "YYYY-MM").
+//
+//	0 practices → 0
+//	1 practice  → AdultFeeSingle (200)
+//	2+          → AdultFeeMonthlyRate[monthKey] or AdultFeeDefault
+func CalculateFee(attendanceCount int, monthKey string) int {
+	if attendanceCount == 0 {
+		return 0
+	}
+	if attendanceCount == 1 {
+		return AdultFeeSingle
+	}
+	if rate, ok := AdultFeeMonthlyRate[monthKey]; ok {
+		return rate
+	}
+	return AdultFeeDefault
+}
--- a/go/internal/domain/fees/fees_test.go
+++ b/go/internal/domain/fees/fees_test.go
@@ -0,0 +1,37 @@
+package fees
+
+import "testing"
+
+func TestCalculateFee(t *testing.T) {
+	t.Parallel()
+
+	// All expected outputs verified against live Python implementation on 2026-05-06:
+	//   PYTHONPATH=scripts:. python -c 'from attendance import calculate_fee; print([calculate_fee(c,m) for c,m in [(0,"2026-05"),(0,""),(1,"2026-05"),(1,"unknown"),(2,"2026-05"),(2,"2026-03"),(2,"2025-09"),(5,"2026-05"),(2,"2027-01"),(2,"")]])'
+	tests := []struct {
+		name  string
+		count int
+		month string
+		want  int
+	}{
+		{"zero short-circuits", 0, "2026-05", 0},
+		{"zero empty month", 0, "", 0},
+		{"single practice", 1, "2026-05", 200},
+		{"single ignores monthKey", 1, "unknown", 200},
+		{"two practices configured month", 2, "2026-05", 700},
+		{"two practices reduced march", 2, "2026-03", 350},
+		{"two practices early season", 2, "2025-09", 750},
+		{"high count same as two", 5, "2026-05", 700},
+		{"unknown future month falls back", 2, "2027-01", 700},
+		{"empty month falls back", 2, "", 700},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			got := CalculateFee(tc.count, tc.month)
+			if got != tc.want {
+				t.Errorf("CalculateFee(%d, %q) = %d, want %d", tc.count, tc.month, got, tc.want)
+			}
+		})
+	}
+}
--- a/go/internal/domain/fees/junior.go
+++ b/go/internal/domain/fees/junior.go
@@ -0,0 +1,37 @@
+package fees
+
+const JuniorFeeDefault = 500 // CZK fallback for 2+ practices when month not in JuniorFeeMonthlyRate
+
+// JuniorFeeMonthlyRate mirrors JUNIOR_MONTHLY_RATE in scripts/attendance.py.
+// Months absent from this map fall back to JuniorFeeDefault.
+var JuniorFeeMonthlyRate = map[string]int{
+	"2025-09": 250,
+	"2026-03": 250,
+}
+
+// Expected is the result of a junior fee calculation.
+// When Unknown is true the fee requires manual review (Python returns "?");
+// in that case Value is meaningless — always check Unknown first.
+type Expected struct {
+	Value   int
+	Unknown bool
+}
+
+// CalculateJuniorFee returns the junior fee for attendanceCount practices in
+// the given monthKey (format "YYYY-MM").
+//
+//	0 practices → Expected{Value: 0}
+//	1 practice  → Expected{Unknown: true}  (manual review; Python sentinel "?")
+//	2+          → Expected{Value: JuniorFeeMonthlyRate[monthKey] or JuniorFeeDefault}
+func CalculateJuniorFee(attendanceCount int, monthKey string) Expected {
+	if attendanceCount == 0 {
+		return Expected{Value: 0}
+	}
+	if attendanceCount == 1 {
+		return Expected{Unknown: true}
+	}
+	if rate, ok := JuniorFeeMonthlyRate[monthKey]; ok {
+		return Expected{Value: rate}
+	}
+	return Expected{Value: JuniorFeeDefault}
+}
--- a/go/internal/domain/fees/junior_test.go
+++ b/go/internal/domain/fees/junior_test.go
@@ -0,0 +1,37 @@
+package fees
+
+import "testing"
+
+func TestCalculateJuniorFee(t *testing.T) {
+	t.Parallel()
+
+	// All expected outputs verified against live Python implementation on 2026-05-06:
+	//   PYTHONPATH=scripts:. python -c 'from attendance import calculate_junior_fee; print([calculate_junior_fee(c,m) for c,m in [(0,"2026-05"),(0,""),(1,"2026-05"),(1,"unknown"),(2,"2026-05"),(2,"2025-09"),(2,"2026-03"),(5,"2025-09"),(2,"2027-01"),(2,"")]])'
+	tests := []struct {
+		name  string
+		count int
+		month string
+		want  Expected
+	}{
+		{"zero short-circuits", 0, "2026-05", Expected{Value: 0}},
+		{"zero empty month", 0, "", Expected{Value: 0}},
+		{"single practice sentinel", 1, "2026-05", Expected{Unknown: true}},
+		{"single ignores monthKey", 1, "unknown", Expected{Unknown: true}},
+		{"two practices default month", 2, "2026-05", Expected{Value: 500}},
+		{"two practices reduced sept", 2, "2025-09", Expected{Value: 250}},
+		{"two practices reduced march", 2, "2026-03", Expected{Value: 250}},
+		{"high count same as two", 5, "2025-09", Expected{Value: 250}},
+		{"unknown future month falls back", 2, "2027-01", Expected{Value: 500}},
+		{"empty month falls back", 2, "", Expected{Value: 500}},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			got := CalculateJuniorFee(tc.count, tc.month)
+			if got != tc.want {
+				t.Errorf("CalculateJuniorFee(%d, %q) = %+v, want %+v", tc.count, tc.month, got, tc.want)
+			}
+		})
+	}
+}
Author	SHA1	Message	Date
Jan Novak	fa853780db	chore: tick M2.3 + M2.4 in progress tracker + CHANGELOG entry All checks were successful Deploy to K8s / deploy (push) Successful in 8s Details Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-06 09:25:45 +02:00
kacerr	0fc3b6dd9a	Merge pull request 'feat(go/M2.3+M2.4): port domain/fees.CalculateFee and CalculateJuniorFee' (#6 ) from feat/m2-3-m2-4-domain-fees into main All checks were successful Deploy to K8s / deploy (push) Successful in 10s Details Reviewed-on: #6	2026-05-06 07:23:02 +00:00
Jan Novak	57ec817044	feat(go/M2.3+M2.4): port domain/fees.CalculateFee and CalculateJuniorFee All checks were successful Deploy to K8s / deploy (push) Successful in 6s Details Ports calculate_fee and calculate_junior_fee from scripts/attendance.py into a new go/internal/domain/fees package. Introduces the Expected type (Value int, Unknown bool) for the junior "?" sentinel, keeping the Go API strictly typed instead of mirroring Python's str\|int return. All 20 table-driven tests pass with -race; golangci-lint clean. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-06 00:38:09 +02:00
Jan Novak	6cf83a01e3	docs(claude): correct stale adult fee defaults ADULT_FEE_DEFAULT is 700 CZK, not 750. The 750 appears in ADULT_FEE_MONTHLY_RATE for most current months but is not the fallback. Rephrase the member-tiers bullet to point at the dict rather than a number that drifts each season; update the fee-calc bullet to match the junior line's style (default 700 vs default 500). Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-06 00:29:19 +02:00
Jan Novak	98f401c149	chore: tick M2.2 in progress tracker + CHANGELOG entry All checks were successful Deploy to K8s / deploy (push) Successful in 9s Details Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-06 00:10:44 +02:00
kacerr	0a8017fffa	Merge pull request 'feat(go/M2.2): port czech.ParseMonthReferences' (#5 ) from feat/m2-2-parse-month-references into main All checks were successful Deploy to K8s / deploy (push) Successful in 10s Details Reviewed-on: #5	2026-05-05 22:07:15 +00:00
Jan Novak	6d971b61d4	feat(go/M2.2): port czech.ParseMonthReferences All checks were successful Deploy to K8s / deploy (push) Successful in 8s Details Three-pass regex parser matching python/czech_utils.py parse_month_references: 1. Numeric slash notation — "11+12/2025", "01/26"; 2-digit year → +2000 2. Dot notation — "12.2025" (4-digit year only) 3. Czech month names — range walk (listopad-leden wrap logic) then standalone with m≥10 → defaultYear-1 heuristic; longest-match alternation (sorted desc by name length) handles cervenec vs cerven 35 table-driven tests, all expected outputs verified against live Python on 2026-05-05 before locking. Plan at docs/plans/2026-05-05-2337-go-rewrite-m2-2-parse-month-references.md. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-06 00:05:40 +02:00
Jan Novak	3460f57c62	chore: tick M2.1 in progress tracker + CHANGELOG entry All checks were successful Deploy to K8s / deploy (push) Successful in 9s Details go/internal/domain/czech.Normalize merged as `20ade6d` (PR #4). Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-05 23:34:00 +02:00
Jan Novak	6ca35e2112	docs: Encourage tea CLI for opening MRs Replaces the "do not use tea/gh/Gitea API" rule with explicit guidance to run `tea pr create` and print the resulting PR URL. tea is already authenticated on this machine. Merging stays a manual user action in Gitea — neither tea nor git CLI may merge or delete branches. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-05 23:33:31 +02:00
kacerr	20ade6de3e	Merge pull request 'feat(go/M2.1): port czech.Normalize' (#4 ) from feat/m2-1-czech-normalize into main All checks were successful Deploy to K8s / deploy (push) Successful in 10s Details Reviewed-on: #4	2026-05-05 21:26:55 +00:00
Jan Novak	d9a61b338c	feat(go/M2.1): port czech.Normalize — NFKD + Mn strip + lowercase All checks were successful Deploy to K8s / deploy (push) Successful in 8s Details Adds internal/domain/czech.Normalize, the first pure-domain function in the Go rewrite (M2 milestone). Matches Python czech_utils.normalize byte- for-byte: NFKD decompose via golang.org/x/text/unicode/norm, drop Mn- category combining marks (unicode.Mn, not IsMark, to match Python's unicodedata.combining() semantics), then strings.ToLower. Includes 13-case table-driven test; all inputs spot-checked against the Python implementation before locking. Adds golang.org/x/text v0.36.0 as first external dependency. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-05 22:23:40 +02:00
Jan Novak	91ac3b37cf	docs: Add branch-per-feature + Gitea MR workflow to CLAUDE.md Feature work now goes on feat/<slug> branches; Claude pushes and prints the Gitea compare URL for the user to open the MR. Exceptions documented for small fixes and typo tweaks. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>	2026-05-05 21:52:25 +02:00