fix(python): parse Fio 2-digit-year dates + add make sync-debug

Fio's transparent page now serves recent rows as DD.MM.YY while older
rows stay DD.MM.YYYY. parse_czech_date only knew the 4-digit form so
every recent transfer was silently dropped — make sync-2026 reported
zero new transactions. Adds %d.%m.%y and %d/%m/%y to the format list,
mirroring the Go-side fix from 2026-05-07.

Also adds a Python analog of make go-sync-debug:
- --dry-run skips header write / append / sort and prints "would …" lines
- --print-fio-table prints aligned per-txn table with NEW/DUP status
- make sync-debug [DAYS=N] wrapper (default DAYS=30)
- always-on stderr diagnostics in fio_utils: which fetcher was chosen
  (with FIO_API_TOKEN-unset lag warning) + raw-vs-filtered counts, so
  this class of "scraper drops everything" bug surfaces immediately.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,20 @@
 # Changelog
 
+## 2026-05-11 22:56 CEST — fix(python): parse Fio 2-digit-year dates + add `make sync-debug` dry-run tool
+
+- Fix: `scripts/fio_utils.py` `parse_czech_date` now accepts `DD.MM.YY` / `D.M.YY` in addition to the 4-digit-year variants. Fio's transparent page now mixes both forms in the same response; the 2-digit rows were being silently dropped, which caused `make sync-2026` to miss every recent transfer. Mirrors the Go-side fix from 2026-05-07 (CHANGELOG entry below).
+- Added `--dry-run` and `--print-fio-table` flags to `scripts/sync_fio_to_sheets.py`, plus a `make sync-debug [DAYS=N]` Makefile target. Mirrors `make go-sync-debug`: fetches from Fio and dedupes against the sheet, prints `STATUS=NEW/DUP` per transaction, and prints per-row `Dry run: would append …` lines + `would sort by date` instead of touching the sheet.
+- Added always-on stderr diagnostics in `scripts/fio_utils.py`: which fetcher was selected (authenticated API vs. transparent-page scraper with `FIO_API_TOKEN`-unset warning), and raw-vs-after-filter transaction counts on both paths — so this class of "scraper drops everything" bug surfaces immediately.
+
+## 2026-05-08 14:55 CEST — feat(go): M6.6.1 — Pay-button QR popup modal
+
+- Restored the Python `showPayQR` in-page modal UX that was lost in M6.6 (Pay buttons were navigating the tab to the raw `/qr` PNG).
+- Replaced `<a href="{{qrHref ...}}">Pay</a>` with `<button data-name|amount|month|raw-month>` on `/adults` and `/juniors`; click is handled by a new `static/js/payment-qr.js` IIFE module that opens `#qrModal` with title, account, amount, message, and the QR image.
+- Added `#qrModal` markup to both templates; CSS `display:none` / `.active{display:flex}` rules added (content rules were already present from M6.1). `Esc`, `[close]`, and outside-click all dismiss; coexists with the M6.5 member-detail modal.
+- Removed the now-dead `qrHref` / `qrHrefAll` template helpers from `render.go`.
+- Markup tests in `html_handler_test.go` assert modal IDs, script tag, `data-bank-account`, and that no bare `href="/qr"` links remain.
+- Key files: `go/internal/web/static/js/payment-qr.js`, `go/internal/web/templates/adults.tmpl`, `go/internal/web/templates/juniors.tmpl`, `go/internal/web/render.go`, `go/internal/web/static/css/app.css`.
+
 ## 2026-05-08 13:57 CEST — feat(go): M6.6 — /qr, /sync-bank, /flush-cache, /version
 
 - Added `GET /qr`: generates Czech QR Platba PNG from SPD payload (account, amount, message query params); ports Python's `qr_code()` handler exactly including account validation, amount clamping, and `*` stripping.

Makefile

@@ -35,6 +35,7 @@ help:
 	@echo "  make sync        - Sync Fio transactions to Google Sheets"
 	@echo "  make sync-2025   - Sync Fio transactions for Q4 2025 (Oct-Dec)"
 	@echo "  make sync-2026   - Sync Fio transactions for the whole year of 2026"
+	@echo "  make sync-debug [DAYS=N] - Dry-run Python sync with Fio diagnostics and txn table (default DAYS=30)"
 	@echo "  make infer       - Infer payment details (Person, Purpose, Amount) in the sheet"
 	@echo "  make reconcile   - Show balance report using Google Sheets data"
 	@echo "  make venv        - Sync virtual environment with pyproject.toml"
@@ -125,6 +126,9 @@ sync-2025: $(PYTHON)
 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
 
+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
+
 infer: $(PYTHON)
 	$(PYTHON) scripts/infer_payments.py --credentials $(CREDENTIALS)
 

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:** M6 — Go-native HTML frontend
 **Started:** 2026-05-04
-**Last updated:** 2026-05-08 (M6.4 merged)
+**Last updated:** 2026-05-08 (M6.6 + M6.6.1 merged)
 
 ## How to use
 
@@ -115,7 +115,8 @@ Goal: feature-equivalent UX on the Go side, designed cleanly. Not a Jinja port.
 - [x] **M6.3** `/juniors` page: same structure + per-month J/A attendance breakdown + `"?"` sentinel rendering — `9564103`
 - [x] **M6.4** `/payments` page: grouped-by-person ledger view — `689f1c0`
 - [x] **M6.5** Modal JS module (`static/js/member-detail.js`): fetches `/api/adults` (or juniors), renders status/exceptions/transactions on row click; keyboard nav (Esc, ↑/↓) — `e53e238`
-- [x] **M6.6** `/qr`, `/sync-bank`, `/flush-cache`, `/version` pages
+- [x] **M6.6** `/qr`, `/sync-bank`, `/flush-cache`, `/version` pages — `f6ba85b`
+- [x] **M6.6.1** Pay-button QR popup modal (`payment-qr.js`); restores Python `showPayQR` UX lost in M6.6 — `4276d7b`
 - [ ] **M6.7** Wire `embed.FS` into handlers; verify single-binary deployment includes all assets
 
 **Gate:** Browser smoke on :8080: all pages render, name+month filters work, modal opens with correct data, QR loads, sync/flush work end-to-end.

docs/plans/2026-05-08-1439-go-m6-6-1-payment-qr-modal.md

@@ -0,0 +1,335 @@
+# M6.6.1 — Pay-button QR popup modal (`/adults`, `/juniors`)
+
+> Plan-mode note: per project convention this plan should live at
+> `docs/plans/2026-05-08-1439-go-m6-6-1-payment-qr-modal.md`. The first
+> execution step after approval is to copy this file there.
+> Branch: `feat/go-m6-6-1-payment-qr-modal` off `main`.
+
+## Context
+
+M6.6 ([docs/plans/2026-05-08-1334-go-m6-6-action-pages.md](docs/plans/2026-05-08-1334-go-m6-6-action-pages.md))
+landed the backend `/qr` PNG endpoint plus `/sync-bank`, `/flush-cache`,
+`/version`. While doing it, the **client-side** half of the Pay flow was
+collapsed from a modal-with-details into a plain `<a href="/qr?...">` —
+clicking Pay now navigates the whole tab to the raw PNG.
+
+The Python app instead opens an in-page `#qrModal` showing the QR image
+*plus* labelled details (account, amount, message, title), then closes
+the modal on outside-click or `[close]`
+([templates/adults.html:631-648](templates/adults.html#L631-L648),
+JS at [templates/adults.html:963-993](templates/adults.html#L963-L993)).
+This is the UX the user expects from the dashboard — staying on the
+table while displaying the QR is significantly more practical than
+losing context to a fullscreen image.
+
+M6.6.1 restores parity: the Pay/Pay-All buttons open an in-page
+`#qrModal`, identical in structure to the Python original, driven by a
+new vanilla-JS module `payment-qr.js` that mirrors the `member-detail.js`
+convention from M6.5.
+
+All the building blocks are already in place:
+
+- **`/qr` endpoint** ships PNGs ([go/internal/web/qr.go](go/internal/web/qr.go), tested by [TestServeQR](go/internal/web/html_handler_test.go#L207-L231)).
+- **CSS** for `#qrModal .modal-content`, `.qr-image`, `.qr-details` is
+  already in [go/internal/web/static/css/app.css:445-478](go/internal/web/static/css/app.css#L445-L478) — lifted during M6.1.
+- **Template helpers** `qrHref` / `qrHrefAll` ([go/internal/web/render.go:63-85](go/internal/web/render.go#L63-L85))
+  already produce the correct query string + Czech `MM/YYYY` format
+  for the `message=` param. They're useful for sanity (and for any
+  no-JS fallback) but become dead code post-M6.6.1 — see §Out of scope.
+- **Bank account** is already exposed as `$.Data.BankAccount` to every
+  template that has a Pay button.
+- **JS module convention**: `member-detail.js` is the M6.5 baseline —
+  IIFE, `'use strict'`, event delegation off `data-*` attributes, no
+  inline `onclick`, no globals leaked.
+
+## Approach
+
+### 1. Replace `<a href="{{qrHref ...}}">` with `<button data-...>`
+
+In [go/internal/web/templates/adults.tmpl](go/internal/web/templates/adults.tmpl)
+and [go/internal/web/templates/juniors.tmpl](go/internal/web/templates/juniors.tmpl)
+(both have identical Pay markup at lines 65 and 72):
+
+```gotmpl
+<button type="button" class="pay-btn"
+        data-name="{{$row.Name}}"
+        data-amount="{{$cell.Amount}}"
+        data-month="{{$cell.Month}}"
+        data-raw-month="{{$cell.RawMonth}}">Pay</button>
+```
+
+```gotmpl
+<button type="button" class="pay-btn"
+        data-name="{{$row.Name}}"
+        data-amount="{{$row.PayableAmount}}"
+        data-month="{{$row.UnpaidPeriods}}"
+        data-raw-month="{{$row.RawUnpaidPeriods}}"
+        data-pay-all="1">Pay All</button>
+```
+
+Why `<button type="button">` and not `<a>`: the click no longer
+navigates — the JS handles it. `type="button"` prevents accidental form
+submission. A no-JS fallback could be added later by re-introducing
+`href="{{qrHref ...}}"` and letting the JS call `e.preventDefault()` —
+deferred until anyone actually asks (see §Out of scope).
+
+`data-month` carries the human-readable period (e.g. `January 2026`,
+or `January 2026 + February 2026` for Pay-All) which the modal title
+displays. `data-raw-month` carries the machine format (`2026-01`,
+`2026-01+2026-02`) which the JS converts to `MM/YYYY` for the QR
+message — same conversion Python's `showPayQR` does at
+[templates/adults.html:966-968](templates/adults.html#L966-L968).
+`data-pay-all` is purely informational; the JS doesn't actually need
+it (the same code path handles single + multi-period), but keeping it
+helps debugging and any future analytics.
+
+### 2. Add `#qrModal` markup
+
+Append after the `#memberModal` block in both `adults.tmpl` and
+`juniors.tmpl` (around line 185 of adults, line 165 of juniors), mirroring
+[templates/adults.html:631-648](templates/adults.html#L631-L648) but
+using `class="active"` toggling (the convention M6.5 picked) instead of
+`style.display = 'block'`:
+
+```gotmpl
+<div id="qrModal" onclick="if(event.target===this)this.classList.remove('active')">
+  <div class="modal-content">
+    <div class="modal-header">
+      <div class="modal-title" id="qrTitle">Payment for —</div>
+      <div class="close-btn" onclick="document.getElementById('qrModal').classList.remove('active')">[close]</div>
+    </div>
+    <div class="qr-image">
+      <img id="qrImg" src="" alt="Payment QR Code">
+    </div>
+    <div class="qr-details">
+      <div>Account: <span id="qrAccount"></span></div>
+      <div>Amount: <span id="qrAmount"></span> CZK</div>
+      <div>Message: <span id="qrMessage"></span></div>
+    </div>
+  </div>
+</div>
+```
+
+The CSS already targets `#qrModal .modal-content` directly. To make the
+"hidden by default / visible when `.active`" toggle behave the same
+way `#memberModal` does, the existing CSS rules for `#memberModal`
+(`display:none`, `#memberModal.active { display: flex; }`) need a
+sibling pair for `#qrModal`. Audit `app.css` during implementation:
+- if `#qrModal` already has both rules, no change.
+- if it has only `display:none`, add `#qrModal.active { display: flex; }`.
+- if it has neither, add both.
+
+This is a 2-line CSS adjustment at most; tracked under §Critical files.
+
+### 3. Bank account on the page
+
+The modal needs the bank account string for the `qrAccount` label and
+for building the `/qr?account=…` URL. Two clean options:
+
+**(a)** Read it from the `<button>`'s `data-bank-account` attribute.
+Per-button duplication, but trivially done in templates and keeps the JS
+module's surface tiny.
+
+**(b)** Stamp it once on the page as `<body data-bank-account="…">`
+(or on the existing `#filterContainer`).
+
+**Decision: (b)** — single stamping site, follows the same pattern
+M6.5 used for `data-page` on `#filterContainer`. Add
+`data-bank-account="{{.Data.BankAccount}}"` to `#filterContainer` in
+both templates (one-line edit each).
+
+### 4. Create [go/internal/web/static/js/payment-qr.js](go/internal/web/static/js/payment-qr.js)
+
+A new module loaded with `<script src="/static/js/payment-qr.js" defer></script>`
+right after `member-detail.js` in both templates. Pure ES, no build
+step, IIFE, `'use strict'`. Skeleton — port of Python's `showPayQR`
+([templates/adults.html:963-986](templates/adults.html#L963-L986))
+plus event wiring:
+
+```js
+(function () {
+  'use strict';
+
+  const container = document.getElementById('filterContainer');
+  if (!container) return;
+  const bankAccount = container.dataset.bankAccount || '';
+
+  const modal      = document.getElementById('qrModal');
+  const titleEl    = document.getElementById('qrTitle');
+  const imgEl      = document.getElementById('qrImg');
+  const accountEl  = document.getElementById('qrAccount');
+  const amountEl   = document.getElementById('qrAmount');
+  const messageEl  = document.getElementById('qrMessage');
+  if (!modal || !titleEl || !imgEl || !accountEl || !amountEl || !messageEl) return;
+
+  // Convert "YYYY-MM" → "MM/YYYY"; "+"-joined ranges are converted piece-wise.
+  // Mirrors templates/adults.html:966-968.
+  function toCzechMonth(rawMonth) {
+    return rawMonth.split('+')
+      .map(p => p.replace(/^(\d{4})-(\d{2})$/, '$2/$1'))
+      .join('+');
+  }
+
+  function showQR(name, amount, month, rawMonth) {
+    const numericMonth = toCzechMonth(rawMonth);
+    const message = `${name}: ${numericMonth}`;
+
+    titleEl.innerText   = `Payment for ${month}`;
+    accountEl.innerText = bankAccount;
+    amountEl.innerText  = amount;
+    messageEl.innerText = message;
+
+    const url = '/qr?'
+      + 'account=' + encodeURIComponent(bankAccount)
+      + '&amount=' + encodeURIComponent(amount)
+      + '&message=' + encodeURIComponent(message);
+    imgEl.src = url;
+
+    modal.classList.add('active');
+  }
+
+  function closeQR() { modal.classList.remove('active'); }
+
+  // Event delegation: any .pay-btn click anywhere in the page.
+  document.addEventListener('click', ev => {
+    const btn = ev.target.closest('.pay-btn');
+    if (!btn) return;
+    ev.preventDefault();
+    showQR(
+      btn.dataset.name,
+      btn.dataset.amount,
+      btn.dataset.month,
+      btn.dataset.rawMonth,
+    );
+  });
+
+  document.addEventListener('keydown', e => {
+    if (e.key === 'Escape' && modal.classList.contains('active')) closeQR();
+  });
+}());
+```
+
+Notes:
+
+- **Event delegation** (single listener on `document`) handles both Pay
+  and Pay-All without enumerating buttons. It also survives any future
+  re-render of the table without needing rebinding.
+- **Coexistence with `member-detail.js`**: `member-detail.js` listens
+  for `Escape` too, but only acts when `#memberModal` is active; the
+  new module similarly only acts when `#qrModal` is active. No collision.
+- **Pre-warming**: nothing to pre-warm — `/qr` is a tiny on-demand PNG
+  and only fires when the user clicks.
+- **Inline `onclick`** on `[close]` and outside-click in the markup are
+  carried over from the M6.5 modal style; consistent with `#memberModal`.
+  (Switching the project's modal close pattern to data attributes is a
+  separate cleanup, out of scope here.)
+
+### 5. Tests
+
+Extend [go/internal/web/html_handler_test.go](go/internal/web/html_handler_test.go)
+with markup-level checks. Headless-browser JS is out of scope (same
+rationale as M6.5).
+
+In `TestModalMarkup` (or a sibling test, e.g. `TestPaymentQRMarkup`):
+
+- Body for `/adults` and `/juniors` contains
+  `<script src="/static/js/payment-qr.js"`.
+- Body contains `id="qrModal"`, `id="qrImg"`, `id="qrAccount"`,
+  `id="qrAmount"`, `id="qrMessage"`, `id="qrTitle"`.
+- The fixture row's Pay button is rendered as
+  `<button … class="pay-btn" … data-name="Test Member" data-amount="…" data-raw-month="2026-01"`.
+- The fixture row's `.pay-btn` does **not** include `href=`.
+- `#filterContainer` has `data-bank-account="CZ0000000000000000000000"`
+  (matching the test's `fixtureHandler` config).
+
+### 6. Decide fate of `qrHref` / `qrHrefAll` template helpers
+
+Once Pay/Pay-All buttons are JS-driven, the helpers in
+[render.go:63-85](go/internal/web/render.go#L63-L85) have no callers.
+**Decision: delete them**, plus their entries in `tmplFuncs`. A
+no-JS fallback is not on the roadmap; if it ever becomes one, the
+helpers are easy to resurrect from git.
+
+The unit-test file currently has no direct tests for these helpers —
+nothing to remove from tests.
+
+## Critical files
+
+| Action | Path |
+|--------|------|
+| edit   | [go/internal/web/templates/adults.tmpl](go/internal/web/templates/adults.tmpl) — Pay/Pay-All → `<button data-…>`; add `#qrModal`; add `data-bank-account` on filter container; add `<script src="/static/js/payment-qr.js" defer>` |
+| edit   | [go/internal/web/templates/juniors.tmpl](go/internal/web/templates/juniors.tmpl) — same |
+| new    | `go/internal/web/static/js/payment-qr.js` — modal module |
+| edit   | [go/internal/web/render.go](go/internal/web/render.go) — drop `qrHref`, `qrHrefAll`, and their `tmplFuncs` entries (and the `net/url`, `strconv` imports if no longer needed) |
+| edit   | [go/internal/web/static/css/app.css](go/internal/web/static/css/app.css) — verify / add `#qrModal { display:none; }` + `#qrModal.active { display:flex; }` rules |
+| edit   | [go/internal/web/html_handler_test.go](go/internal/web/html_handler_test.go) — markup assertions |
+
+No changes to: `assets.go` (`embed.FS` glob picks up new JS automatically),
+`server.go`, `html_handler.go`, the `/qr` handler, `cmd/fuj/main.go`, the
+API handlers, or any domain code.
+
+## Reused existing infrastructure
+
+- [go/internal/web/qr.go](go/internal/web/qr.go) — `/qr?account=…&amount=…&message=…` endpoint serves the PNG already
+- [go/internal/web/static/css/app.css:445-478](go/internal/web/static/css/app.css#L445-L478) — modal CSS already lifted whole
+- [go/internal/web/static/js/member-detail.js](go/internal/web/static/js/member-detail.js) — IIFE / `'use strict'` / `data-*` style to mirror
+- [go/internal/web/api/types.go](go/internal/web/api/types.go) — `MemberRow.UnpaidPeriods` and `RawUnpaidPeriods` already populated for Pay-All
+- [templates/adults.html:631-648,963-986](templates/adults.html#L631-L648) — Python reference for both modal markup and `showPayQR` JS (logic to port, not literal copy)
+
+## Verification
+
+End-to-end, after copying the plan into `docs/plans/`:
+
+1. `cd go && make go-build go-test go-lint` — all green.
+2. `make web-go &` — boot Go on `:8080`.
+3. Browser: `http://localhost:8080/adults`
+   - Click `Pay` on any unpaid month → `#qrModal` opens with
+     - title `Payment for <Month YYYY>`,
+     - `qrAccount` matching `BANK_ACCOUNT`,
+     - `qrAmount` matching the cell amount,
+     - `qrMessage` formatted as `<Name>: MM/YYYY`,
+     - QR image rendered from `/qr?…` (Network tab shows PNG response).
+   - Tab does **not** navigate; URL stays `/adults`.
+   - Click `Pay All` → modal opens with `+`-joined `MM/YYYY+MM/YYYY` message.
+   - Click outside the modal-content → modal closes.
+   - Click `[close]` → modal closes.
+   - Press `Esc` → modal closes.
+   - Open `[i]` member-detail modal first, then `Esc` → only that closes
+     (verify both modals don't fight each other).
+4. Browser: `http://localhost:8080/juniors` — same checks. Verify Pay
+   on a `"?"`-expected row doesn't appear (Pay button is conditional on
+   `unpaid`/`partial` cells).
+5. Cross-check against Python: `make web-py &` →
+   `http://localhost:5001/adults` modal looks visually equivalent for
+   the same fixture (modulo any nav / theme differences already accepted
+   in M6).
+6. Scan a QR with a Czech banking app (or `zbarimg` on the saved PNG) —
+   payload starts with `SPD*1.0*ACC:` and the message decodes to
+   `<Name>: MM/YYYY`.
+7. After the user merges in Gitea: append CHANGELOG entry (timestamp via
+   `date "+%Y-%m-%d %H:%M %Z"`); add a new tick line for **M6.6.1** in
+   [docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md](docs/plans/2026-05-03-2349-go-backend-rewrite-progress.md)
+   immediately under the M6.6 line, in the same format as the other
+   sub-bullets.
+
+## Branching
+
+Per [CLAUDE.md](CLAUDE.md): create `feat/go-m6-6-1-payment-qr-modal` off
+`main`, commit with `Co-Authored-By` trailer, push with `-u`, open MR via
+`tea pr create`. Do not merge or delete from CLI.
+
+## Out of scope (deferred)
+
+- **Pay button no-JS fallback** — feasible to keep `qrHref` and have
+  the JS `preventDefault` an `<a>`, but no current need. Resurrect the
+  helpers if asked.
+- **Modal pattern unification** — `#memberModal` and `#qrModal` use
+  inline `onclick` for `[close]` and outside-click. Consistent with
+  M6.5 but worth a follow-up to delegate-event everything.
+- **Pay-from-modal inside `#memberModal`** — Python doesn't have it, and
+  no one's asked for it on the Go side.
+- **Per-button QR error-correction / size** — `/qr` is fixed at
+  Medium/256, same as M6.6. Configurable via query param can be added if
+  printing larger physical posters becomes a use case.
+- **`/payments` Pay buttons** — the payments page is a ledger view; it
+  doesn't render Pay buttons in either backend.

go/internal/web/html_handler_test.go

@@ -314,6 +314,52 @@ func TestServeSync(t *testing.T) {
 	}
 }
 
+func TestPaymentQRMarkup(t *testing.T) {
+	renderer, err := web.NewRenderer()
+	if err != nil {
+		t.Fatalf("NewRenderer: %v", err)
+	}
+	b := web.BuildInfo{Version: "v0", Commit: "abc1234", BuildDate: "2026-01-01"}
+	h := web.NewHTMLHandler(renderer, b, fixtureHandler(t), web.ActionHandlers{})
+
+	cases := []struct {
+		path    string
+		handler http.HandlerFunc
+	}{
+		{"/adults", h.ServeAdults},
+		{"/juniors", h.ServeJuniors},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.path, func(t *testing.T) {
+			req := httptest.NewRequest(http.MethodGet, tc.path, nil)
+			w := httptest.NewRecorder()
+			tc.handler(w, req)
+			body := w.Body.String()
+
+			for _, want := range []string{
+				`id="qrModal"`,
+				`id="qrImg"`,
+				`id="qrTitle"`,
+				`id="qrAccount"`,
+				`id="qrAmount"`,
+				`id="qrMessage"`,
+				`/static/js/payment-qr.js`,
+				`data-bank-account="CZ0000000000000000000000"`,
+			} {
+				if !strings.Contains(body, want) {
+					t.Errorf("body missing %q", want)
+				}
+			}
+
+			// Pay buttons must use <button>, never a bare href to /qr.
+			if strings.Contains(body, `href="/qr`) {
+				t.Error("body must not contain href=/qr (Pay buttons should be <button>, not <a>)")
+			}
+		})
+	}
+}
+
 func TestServeVersion(t *testing.T) {
 	req := httptest.NewRequest(http.MethodGet, "/api/version", nil)
 	w := httptest.NewRecorder()

go/internal/web/render.go

@@ -6,8 +6,6 @@ import (
 	"html/template"
 	"log/slog"
 	"net/http"
-	"net/url"
-	"strconv"
 )
 
 // PageData is the view model passed to every HTML template.
@@ -58,36 +56,7 @@ type Renderer struct {
 
 var pageNames = []string{"adults", "juniors", "payments", "sync", "flush_cache"}
 
-// qrHref builds the /qr query URL for a single-month Pay button.
-// rawMonth is "YYYY-MM"; it is converted to "MM/YYYY" in the QR message.
-func qrHref(account string, amount int, name, rawMonth string) string {
-	// Convert "YYYY-MM" → "MM/YYYY" to match Python's showPayQR JS.
-	if len(rawMonth) == 7 && rawMonth[4] == '-' {
-		rawMonth = rawMonth[5:] + "/" + rawMonth[:4]
-	}
-	msg := name + ": " + rawMonth
-	return "/qr?" + url.Values{
-		"account": {account},
-		"amount":  {strconv.Itoa(amount)},
-		"message": {msg},
-	}.Encode()
-}
-
-// qrHrefAll builds the /qr query URL for a Pay-All button.
-// rawPeriods is the "+" -joined MM/YYYY string from MemberRow.RawUnpaidPeriods.
-func qrHrefAll(account string, amount int, name, rawPeriods string) string {
-	msg := name + ": " + rawPeriods
-	return "/qr?" + url.Values{
-		"account": {account},
-		"amount":  {strconv.Itoa(amount)},
-		"message": {msg},
-	}.Encode()
-}
-
-var tmplFuncs = template.FuncMap{
-	"qrHref":    qrHref,
-	"qrHrefAll": qrHrefAll,
-}
+var tmplFuncs = template.FuncMap{}
 
 // NewRenderer parses all templates from the embedded FS.
 // A parse failure should be treated as a startup-time fatal error.

go/internal/web/static/css/app.css

@@ -442,6 +442,23 @@ tr:hover {
 }
 
 /* QR Modal styles */
+#qrModal {
+    display: none !important;
+    position: fixed;
+    top: 0;
+    left: 0;
+    width: 100vw;
+    height: 100vh;
+    background-color: rgba(0, 0, 0, 0.9);
+    z-index: 9999;
+    justify-content: center;
+    align-items: center;
+}
+
+#qrModal.active {
+    display: flex !important;
+}
+
 #qrModal .modal-content {
     max-width: 400px;
     text-align: center;

go/internal/web/static/js/payment-qr.js

@@ -0,0 +1,60 @@
+(function () {
+  'use strict';
+
+  const container = document.getElementById('filterContainer');
+  if (!container) return;
+  const bankAccount = container.dataset.bankAccount || '';
+
+  const modal     = document.getElementById('qrModal');
+  const titleEl   = document.getElementById('qrTitle');
+  const imgEl     = document.getElementById('qrImg');
+  const accountEl = document.getElementById('qrAccount');
+  const amountEl  = document.getElementById('qrAmount');
+  const messageEl = document.getElementById('qrMessage');
+  if (!modal || !titleEl || !imgEl || !accountEl || !amountEl || !messageEl) return;
+
+  // Convert "YYYY-MM" → "MM/YYYY"; "+"-joined ranges converted piece-wise.
+  // Mirrors templates/adults.html showPayQR logic.
+  function toCzechMonth(rawMonth) {
+    return rawMonth.split('+')
+      .map(function (p) { return p.replace(/^(\d{4})-(\d{2})$/, '$2/$1'); })
+      .join('+');
+  }
+
+  function showQR(name, amount, month, rawMonth) {
+    var numericMonth = toCzechMonth(rawMonth);
+    var message = name + ': ' + numericMonth;
+
+    titleEl.innerText   = 'Payment for ' + month;
+    accountEl.innerText = bankAccount;
+    amountEl.innerText  = amount;
+    messageEl.innerText = message;
+
+    imgEl.src = '/qr?'
+      + 'account=' + encodeURIComponent(bankAccount)
+      + '&amount=' + encodeURIComponent(amount)
+      + '&message=' + encodeURIComponent(message);
+
+    modal.classList.add('active');
+  }
+
+  function closeQR() {
+    modal.classList.remove('active');
+  }
+
+  document.addEventListener('click', function (ev) {
+    var btn = ev.target.closest('.pay-btn');
+    if (!btn) return;
+    ev.preventDefault();
+    showQR(
+      btn.dataset.name,
+      btn.dataset.amount,
+      btn.dataset.month,
+      btn.dataset.rawMonth
+    );
+  });
+
+  document.addEventListener('keydown', function (e) {
+    if (e.key === 'Escape' && modal.classList.contains('active')) closeQR();
+  });
+}());

go/internal/web/templates/adults.tmpl

@@ -12,7 +12,7 @@
   <a href="{{.Data.PaymentsURL}}" target="_blank" rel="noopener">Payments Ledger</a>
 </div>
 
-<div class="filter-container" id="filterContainer" data-current-month="{{.Data.CurrentMonth}}" data-page="adults">
+<div class="filter-container" id="filterContainer" data-current-month="{{.Data.CurrentMonth}}" data-page="adults" data-bank-account="{{.Data.BankAccount}}">
   <div class="filter-item">
     <label class="filter-label" for="nameFilter">Member</label>
     <input id="nameFilter" class="filter-input" type="text" placeholder="Filter by name…">
@@ -62,14 +62,14 @@
           class="{{if eq $cell.Status "empty"}}cell-empty{{else if and (or (eq $cell.Status "unpaid") (eq $cell.Status "partial")) (ge $cell.RawMonth $.Data.CurrentMonth)}}cell-unpaid-current{{else if or (eq $cell.Status "unpaid") (eq $cell.Status "partial")}}cell-unpaid{{else if eq $cell.Status "ok"}}cell-ok{{end}}{{if $cell.Overridden}} cell-overridden{{end}}">
         {{$cell.Text}}
         {{if and (or (eq $cell.Status "unpaid") (eq $cell.Status "partial")) (lt $cell.RawMonth $.Data.CurrentMonth)}}
-        <a class="pay-btn" href="{{qrHref $.Data.BankAccount $cell.Amount $row.Name $cell.RawMonth}}">Pay</a>
+        <button type="button" class="pay-btn" data-name="{{$row.Name}}" data-amount="{{$cell.Amount}}" data-month="{{$cell.Month}}" data-raw-month="{{$cell.RawMonth}}">Pay</button>
         {{end}}
       </td>
       {{end}}
       <td class="{{if lt $row.Balance 0}}balance-neg{{else if gt $row.Balance 0}}balance-pos{{end}}" style="position: relative;">
         {{$row.Balance}}
         {{if gt $row.PayableAmount 0}}
-        <a class="pay-btn" href="{{qrHrefAll $.Data.BankAccount $row.PayableAmount $row.Name $row.RawUnpaidPeriods}}">Pay All</a>
+        <button type="button" class="pay-btn" data-name="{{$row.Name}}" data-amount="{{$row.PayableAmount}}" data-month="{{$row.UnpaidPeriods}}" data-raw-month="{{$row.RawUnpaidPeriods}}" data-pay-all="1">Pay All</button>
         {{end}}
       </td>
     </tr>
@@ -184,6 +184,24 @@
   </div>
 </div>
 
+<div id="qrModal" onclick="if(event.target===this)this.classList.remove('active')">
+  <div class="modal-content">
+    <div class="modal-header">
+      <div class="modal-title" id="qrTitle">Payment for —</div>
+      <div class="close-btn" onclick="document.getElementById('qrModal').classList.remove('active')">[close]</div>
+    </div>
+    <div class="qr-image">
+      <img id="qrImg" src="" alt="Payment QR Code">
+    </div>
+    <div class="qr-details">
+      <div>Account: <span id="qrAccount"></span></div>
+      <div>Amount: <span id="qrAmount"></span> CZK</div>
+      <div>Message: <span id="qrMessage"></span></div>
+    </div>
+  </div>
+</div>
+
 <script src="/static/js/filters.js" defer></script>
 <script src="/static/js/member-detail.js" defer></script>
+<script src="/static/js/payment-qr.js" defer></script>
 {{end}}

go/internal/web/templates/juniors.tmpl

@@ -12,7 +12,7 @@
   <a href="{{.Data.PaymentsURL}}" target="_blank" rel="noopener">Payments Ledger</a>
 </div>
 
-<div class="filter-container" id="filterContainer" data-current-month="{{.Data.CurrentMonth}}" data-page="juniors">
+<div class="filter-container" id="filterContainer" data-current-month="{{.Data.CurrentMonth}}" data-page="juniors" data-bank-account="{{.Data.BankAccount}}">
   <div class="filter-item">
     <label class="filter-label" for="nameFilter">Member</label>
     <input id="nameFilter" class="filter-input" type="text" placeholder="Filter by name…">
@@ -62,14 +62,14 @@
           class="{{if eq $cell.Status "empty"}}cell-empty{{else if and (or (eq $cell.Status "unpaid") (eq $cell.Status "partial")) (ge $cell.RawMonth $.Data.CurrentMonth)}}cell-unpaid-current{{else if or (eq $cell.Status "unpaid") (eq $cell.Status "partial")}}cell-unpaid{{else if eq $cell.Status "ok"}}cell-ok{{end}}{{if $cell.Overridden}} cell-overridden{{end}}">
         {{$cell.Text}}
         {{if and (or (eq $cell.Status "unpaid") (eq $cell.Status "partial")) (lt $cell.RawMonth $.Data.CurrentMonth)}}
-        <a class="pay-btn" href="{{qrHref $.Data.BankAccount $cell.Amount $row.Name $cell.RawMonth}}">Pay</a>
+        <button type="button" class="pay-btn" data-name="{{$row.Name}}" data-amount="{{$cell.Amount}}" data-month="{{$cell.Month}}" data-raw-month="{{$cell.RawMonth}}">Pay</button>
         {{end}}
       </td>
       {{end}}
       <td class="{{if lt $row.Balance 0}}balance-neg{{else if gt $row.Balance 0}}balance-pos{{end}}" style="position: relative;">
         {{$row.Balance}}
         {{if gt $row.PayableAmount 0}}
-        <a class="pay-btn" href="{{qrHrefAll $.Data.BankAccount $row.PayableAmount $row.Name $row.RawUnpaidPeriods}}">Pay All</a>
+        <button type="button" class="pay-btn" data-name="{{$row.Name}}" data-amount="{{$row.PayableAmount}}" data-month="{{$row.UnpaidPeriods}}" data-raw-month="{{$row.RawUnpaidPeriods}}" data-pay-all="1">Pay All</button>
         {{end}}
       </td>
     </tr>
@@ -164,6 +164,24 @@
   </div>
 </div>
 
+<div id="qrModal" onclick="if(event.target===this)this.classList.remove('active')">
+  <div class="modal-content">
+    <div class="modal-header">
+      <div class="modal-title" id="qrTitle">Payment for —</div>
+      <div class="close-btn" onclick="document.getElementById('qrModal').classList.remove('active')">[close]</div>
+    </div>
+    <div class="qr-image">
+      <img id="qrImg" src="" alt="Payment QR Code">
+    </div>
+    <div class="qr-details">
+      <div>Account: <span id="qrAccount"></span></div>
+      <div>Amount: <span id="qrAmount"></span> CZK</div>
+      <div>Message: <span id="qrMessage"></span></div>
+    </div>
+  </div>
+</div>
+
 <script src="/static/js/filters.js" defer></script>
 <script src="/static/js/member-detail.js" defer></script>
+<script src="/static/js/payment-qr.js" defer></script>
 {{end}}

scripts/fio_utils.py

@@ -4,6 +4,7 @@
 import json
 import os
 import re
+import sys
 import urllib.request
 from datetime import datetime
 from html.parser import HTMLParser
@@ -89,9 +90,11 @@ def parse_czech_amount(s: str) -> float | None:
 
 
 def parse_czech_date(s: str) -> str | None:
-    """Parse 'DD.MM.YYYY' to 'YYYY-MM-DD'."""
+    """Parse a Czech date to 'YYYY-MM-DD'. Accepts 4-digit and 2-digit years
+    with dot or slash separators; Fio's transparent page mixes 'DD.MM.YYYY'
+    and 'DD.MM.YY' in the same response."""
     s = s.strip()
-    for fmt in ("%d.%m.%Y", "%d/%m/%Y"):
+    for fmt in ("%d.%m.%Y", "%d/%m/%Y", "%d.%m.%y", "%d/%m/%y"):
         try:
             return datetime.strptime(s, fmt).strftime("%Y-%m-%d")
         except ValueError:
@@ -146,6 +149,7 @@ def fetch_transactions_transparent(
             "bank_id": "", # HTML scraping doesn't give stable ID
         })
 
+    print(f"fio: transparent fetched {len(rows)} raw rows, {len(transactions)} transaction(s) after filtering", file=sys.stderr)
     return transactions
 
 
@@ -169,7 +173,8 @@ def fetch_transactions_api(
 
     transactions = []
     tx_list = data.get("accountStatement", {}).get("transactionList", {})
-    for tx in (tx_list.get("transaction") or []):
+    raw_list = tx_list.get("transaction") or []
+    for tx in raw_list:
         # Each field is {"value": ..., "name": ..., "id": ...} or null
         def val(col_id):
             col = tx.get(f"column{col_id}")
@@ -197,6 +202,7 @@ def fetch_transactions_api(
             "currency": str(val(14) or "CZK"), # column14 = Currency
         })
 
+    print(f"fio: api fetched {len(raw_list)} raw transaction(s), {len(transactions)} after filtering", file=sys.stderr)
     return transactions
 
 
@@ -204,8 +210,14 @@ def fetch_transactions(date_from: str, date_to: str) -> list[dict]:
     """Fetch transactions, using API if token available, else transparent page."""
     token = os.environ.get("FIO_API_TOKEN", "").strip()
     if token:
+        print(f"fio: using authenticated API, window {date_from}..{date_to}", file=sys.stderr)
         return fetch_transactions_api(token, date_from, date_to)
 
+    print(
+        f"fio: using transparent page (FIO_API_TOKEN unset — expect publishing lag), "
+        f"window {date_from}..{date_to}, account=2800359168",
+        file=sys.stderr,
+    )
     # Convert YYYY-MM-DD to DD.MM.YYYY for the transparent page URL
     from_dt = datetime.strptime(date_from, "%Y-%m-%d")
     to_dt = datetime.strptime(date_to, "%Y-%m-%d")

scripts/sync_fio_to_sheets.py

@@ -77,6 +77,35 @@ def generate_sync_id(tx: dict) -> str:
     return hashlib.sha256(raw_str.encode("utf-8")).hexdigest()
 
 
+def _trunc(s: str, n: int = 40) -> str:
+    s = str(s)
+    return s if len(s) <= n else s[: n - 1] + "…"
+
+
+def _print_fio_table(transactions: list[dict], statuses: list[str]) -> None:
+    headers = ["DATE", "AMOUNT", "SENDER", "VS", "MESSAGE", "BANKID", "STATUS"]
+    rows = [
+        [
+            str(tx.get("date", "")),
+            f"{float(tx.get('amount', 0)):.2f}",
+            str(tx.get("sender", "")),
+            str(tx.get("vs", "")),
+            _trunc(str(tx.get("message", ""))),
+            str(tx.get("bank_id", "")),
+            status,
+        ]
+        for tx, status in zip(transactions, statuses)
+    ]
+    widths = [
+        max(len(headers[i]), max((len(r[i]) for r in rows), default=0))
+        for i in range(len(headers))
+    ]
+    sep = "  "
+    print(sep.join(h.ljust(w) for h, w in zip(headers, widths)))
+    for row in rows:
+        print(sep.join(cell.ljust(w) for cell, w in zip(row, widths)))
+
+
 def sort_sheet_by_date(service, spreadsheet_id):
     """Sort the sheet by the Date column (Column B)."""
     # Get the sheet ID (gid) of the first sheet
@@ -104,12 +133,21 @@ def sort_sheet_by_date(service, spreadsheet_id):
     print("Sheet sorted by date.")
 
 
-def sync_to_sheets(spreadsheet_id: str, credentials_path: str, days: int = None, date_from_str: str = None, date_to_str: str = None, sort_by_date: bool = False):
+def sync_to_sheets(
+    spreadsheet_id: str,
+    credentials_path: str,
+    days: int = None,
+    date_from_str: str = None,
+    date_to_str: str = None,
+    sort_by_date: bool = False,
+    dry_run: bool = False,
+    print_fio_table: bool = False,
+):
     print(f"Connecting to Google Sheets using {credentials_path}...")
     service = get_sheets_service(credentials_path)
     sheet = service.spreadsheets()
 
-    # 1. Fetch existing IDs from Column G (last column in A-G range)
+    # 1. Read existing sync IDs from Column K
     print(f"Reading existing sync IDs from sheet...")
     try:
         result = sheet.values().get(
@@ -117,19 +155,22 @@ def sync_to_sheets(spreadsheet_id: str, credentials_path: str, days: int = None,
             range="A1:K" # Include header and all columns to check Sync ID
         ).execute()
         values = result.get("values", [])
-        
+
         # Check and insert labels if missing
         if not values or values[0] != COLUMN_LABELS:
-            print("Inserting column labels...")
-            sheet.values().update(
-                spreadsheetId=spreadsheet_id,
-                range="A1",
-                valueInputOption="USER_ENTERED",
-                body={"values": [COLUMN_LABELS]}
-            ).execute()
+            if dry_run:
+                print("Dry run: would write header row")
+            else:
+                print("Inserting column labels...")
+                sheet.values().update(
+                    spreadsheetId=spreadsheet_id,
+                    range="A1",
+                    valueInputOption="USER_ENTERED",
+                    body={"values": [COLUMN_LABELS]}
+                ).execute()
             existing_ids = set()
         else:
-            # Sync ID is now the last column (index 10)
+            # Sync ID is the last column (index 10)
             existing_ids = {row[10] for row in values[1:] if len(row) > 10}
     except Exception as e:
         print(f"Error reading sheet (maybe empty?): {e}")
@@ -150,8 +191,12 @@ def sync_to_sheets(spreadsheet_id: str, credentials_path: str, days: int = None,
     transactions = fetch_transactions(df_str, dt_str)
     print(f"Found {len(transactions)} transactions.")
 
-    # 3. Filter for new transactions
+    if dry_run:
+        print(f"Dry run: window {df_str} to {dt_str}, fetched {len(transactions)} transaction(s) from Fio")
+
+    # 3. Determine NEW/DUP for each transaction
     new_rows = []
+    tx_statuses = []
     for tx in transactions:
         sync_id = generate_sync_id(tx)
         if sync_id not in existing_ids:
@@ -169,24 +214,48 @@ def sync_to_sheets(spreadsheet_id: str, credentials_path: str, days: int = None,
                 tx.get("bank_id", ""),
                 sync_id,
             ])
+            tx_statuses.append("NEW")
+        else:
+            tx_statuses.append("DUP")
+
+    # 4. Print table (before early-return so all transactions are shown including DUPs)
+    if print_fio_table and transactions:
+        _print_fio_table(transactions, tx_statuses)
 
     if not new_rows:
-        print("No new transactions to sync.")
+        if dry_run:
+            print("Dry run: would sync 0 new transaction(s).")
+        else:
+            print("No new transactions to sync.")
         return
 
-    # 4. Append to sheet
-    print(f"Appending {len(new_rows)} new transactions to the sheet...")
-    body = {"values": new_rows}
-    sheet.values().append(
-        spreadsheetId=spreadsheet_id,
-        range="A2", # Appends to the end of the sheet
-        valueInputOption="USER_ENTERED",
-        body=body
-    ).execute()
-    print("Sync completed successfully.")
-
-    if sort_by_date:
-        sort_sheet_by_date(service, spreadsheet_id)
+    # 5. Append to sheet or print dry-run would-write lines
+    if dry_run:
+        for tx, status in zip(transactions, tx_statuses):
+            if status == "NEW":
+                print(
+                    f"Dry run: would append"
+                    f" date={tx.get('date', '')}"
+                    f" amount={tx.get('amount', '')}"
+                    f" sender={tx.get('sender', '')}"
+                    f" vs={tx.get('vs', '')}"
+                    f" message={tx.get('message', '')}"
+                )
+        if sort_by_date:
+            print("Dry run: would sort by date")
+        print(f"Dry run: would sync {len(new_rows)} new transaction(s).")
+    else:
+        print(f"Appending {len(new_rows)} new transactions to the sheet...")
+        body = {"values": new_rows}
+        sheet.values().append(
+            spreadsheetId=spreadsheet_id,
+            range="A2", # Appends to the end of the sheet
+            valueInputOption="USER_ENTERED",
+            body=body
+        ).execute()
+        print("Sync completed successfully.")
+        if sort_by_date:
+            sort_sheet_by_date(service, spreadsheet_id)
 
 
 def main():
@@ -197,16 +266,20 @@ def main():
     parser.add_argument("--from", dest="date_from", help="Start date YYYY-MM-DD")
     parser.add_argument("--to", dest="date_to", help="End date YYYY-MM-DD")
     parser.add_argument("--sort-by-date", action="store_true", help="Sort the sheet by date after sync")
+    parser.add_argument("--dry-run", action="store_true", help="Fetch and dedup without writing to the sheet")
+    parser.add_argument("--print-fio-table", action="store_true", help="Print aligned table of all fetched transactions with NEW/DUP status (use with --dry-run)")
     args = parser.parse_args()
 
     try:
         sync_to_sheets(
-            spreadsheet_id=args.sheet_id, 
+            spreadsheet_id=args.sheet_id,
             credentials_path=args.credentials,
             days=args.days,
             date_from_str=args.date_from,
             date_to_str=args.date_to,
-            sort_by_date=args.sort_by_date
+            sort_by_date=args.sort_by_date,
+            dry_run=args.dry_run,
+            print_fio_table=args.print_fio_table,
         )
     except Exception as e:
         print(f"Sync failed: {e}")