feat(19-ui-integration): przycisk Drukuj, bulk print, kolejka wydruku

- Przycisk "Drukuj" w prepare.php i show.php z AJAX + duplikat protection
- Bulk print z listy zamówień (checkboxy + header action)
- Kolejka wydruku w Ustawienia > Drukowanie (filtr statusu, retry)
- POST /api/print/jobs/bulk endpoint (package_ids + order_ids)
- ensureLabel() auto-download przez ShipmentProviderRegistry
- Apaczka carrier_id = nazwa usługi, kolumna Przewoznik
- Tab persistence (localStorage), label file_exists check
- Fix use statement ApaczkaApiClient, redirect po utworzeniu przesyłki
- Phase 17 (receipt duplicate guard) + Phase 18 (print queue backend) docs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.paul/phases/17-receipt-duplicate-guard/17-01-SUMMARY.md

@@ -0,0 +1,99 @@
+---
+phase: 17-receipt-duplicate-guard
+plan: 01
+subsystem: ui
+tags: [receipts, duplicate-guard, OrderProAlerts, confirmation]
+
+requires:
+  - phase: 10-receipt-creation
+    provides: ReceiptController, ReceiptRepository, receipt-create view
+provides:
+  - Duplicate receipt warning on creation form
+  - OrderProAlerts.confirm guard before duplicate receipt submission
+affects: []
+
+tech-stack:
+  added: []
+  patterns: [frontend-guard-with-backend-data]
+
+key-files:
+  created: []
+  modified:
+    - src/Modules/Accounting/ReceiptController.php
+    - resources/views/orders/receipt-create.php
+
+key-decisions:
+  - "Frontend guard only — no server-side block in store(), user confirms consciously"
+  - "Conditional button type (submit vs button) — no JS overhead when no existing receipts"
+
+patterns-established:
+  - "Duplicate-guard pattern: backend query → view warning → OrderProAlerts.confirm on submit"
+
+duration: 5min
+started: 2026-03-22T00:00:00Z
+completed: 2026-03-22T00:05:00Z
+---
+
+# Phase 17 Plan 01: Receipt Duplicate Guard Summary
+
+**Frontend guard preventing accidental duplicate receipt creation — warning box + OrderProAlerts.confirm before submit when order already has receipts.**
+
+## Performance
+
+| Metric | Value |
+|--------|-------|
+| Duration | ~5min |
+| Tasks | 2 completed |
+| Files modified | 2 |
+
+## Acceptance Criteria Results
+
+| Criterion | Status | Notes |
+|-----------|--------|-------|
+| AC-1: Formularz pokazuje ostrzeżenie gdy zamówienie ma paragon | Pass | Warning box z numerem, datą, kwotą, configiem |
+| AC-2: Submit wymaga potwierdzenia gdy istnieją paragony | Pass | button type="button" + OrderProAlerts.confirm |
+| AC-3: Brak ostrzeżenia gdy zamówienie nie ma paragonów | Pass | Warunek PHP $hasExistingReceipts, normalny submit |
+
+## Accomplishments
+
+- Warning box `.alert--warning` z listą istniejących paragonów (numer, data, kwota, config)
+- Conditional submit: `type="button"` + `OrderProAlerts.confirm()` gdy istnieją paragony, normalny `type="submit"` gdy brak
+- Reuse istniejącego `ReceiptRepository::findByOrderId()` — zero nowego kodu backend poza 2 liniami
+
+## Files Created/Modified
+
+| File | Change | Purpose |
+|------|--------|---------|
+| `src/Modules/Accounting/ReceiptController.php` | Modified | Dodanie `findByOrderId()` query + przekazanie `existingReceipts` do widoku |
+| `resources/views/orders/receipt-create.php` | Modified | Warning box, conditional button type, inline JS z OrderProAlerts.confirm |
+
+## Decisions Made
+
+| Decision | Rationale | Impact |
+|----------|-----------|--------|
+| Frontend guard only (brak blokady w store()) | Użytkownik świadomie potwierdza — to wystarczający level ochrony | Prostota, brak zmian w logice zapisu |
+| Conditional button type zamiast always-JS | Brak narzutu JS gdy nie ma istniejących paragonów | Czystsza implementacja |
+
+## Deviations from Plan
+
+None — plan executed exactly as written.
+
+## Issues Encountered
+
+None.
+
+## Next Phase Readiness
+
+**Ready:**
+- Punkt 31 z todo.md zrealizowany
+- Pattern duplicate-guard gotowy do reuse w innych formularzach
+
+**Concerns:**
+- Brak
+
+**Blockers:**
+- None
+
+---
+*Phase: 17-receipt-duplicate-guard, Plan: 01*
+*Completed: 2026-03-22*