feat(125): invoice_requested import fix + drop legacy is_invoice column

- shopPRO: ShopproOrderMapper jako jedyne zrodlo heurystyki detekcji faktury;
  mapOrderAggregate() zwraca top-level invoice_detected (transient).
- ShopproOrdersSyncService: usunieta wlasna shouldRequestInvoice(); propagacja
  aggregate['invoice_detected'] do setInvoiceRequested() tylko przy created=true.
- Allegro: nowa shouldRequestInvoice(payload) z 4 wzorcami (invoice.required,
  naturalPerson=false, address.taxId, companyName/address.company.name).
  Wczesniej tylko invoice.required -> analogiczna luka jak shopPRO.
- Migracja 20260513_000113: idempotentny backfill (UPDATE invoice_requested=1
  WHERE is_invoice=1 AND invoice_requested=0) + DROP COLUMN orders.is_invoice.
  Guard przez information_schema.COLUMNS + PREPARE/EXECUTE z ALTER TABLE COMMENT
  no-op fallbackiem (portable MySQL/MariaDB).
- Cleanup is_invoice z OrderImportRepository (INSERT cols/values/params,
  docstring Phase 112) i OrdersRepository (paginate SELECT, transformOrderRow
  hydrate). AllegroOrderImportService mapping w mapCheckoutFormPayload tez
  usuniety (wymuszone konsekwencja DROP COLUMN).
- Bugfix #1089: zamowienie shopPRO z firm_nip (bez wants_invoice/invoice.required)
  ustawia teraz invoice_requested=1 -> UI w zakladce Platnosci zaznacza checkbox,
  przycisk "Wystaw fakture" widoczny.

Pending operator: php bin/migrate.php (XAMPP MySQL online) -> backfill 7 zamowien.
Smoke test: re-import shopPRO + nowe Allegro z NIP.

.paul/codebase/db_schema.md

@@ -1,6 +1,6 @@
 # Database Schema
 
-**Updated:** 2026-05-12 | **Total tables:** 61 | **Engine:** InnoDB | **Charset:** utf8mb4_unicode_ci
+**Updated:** 2026-05-13 | **Total tables:** 61 | **Engine:** InnoDB | **Charset:** utf8mb4_unicode_ci
 
 ---
 
@@ -275,6 +275,8 @@ UNIQUE: `(integration_id, external_product_id, external_variant_id)`
 UNIQUE: `(integration_id, external_order_id)`
 
 > Note: Order notes are stored in the separate `order_notes` table (no `notes` column on `orders`).
+>
+> Note (Phase 125-01, 2026-05-13): `invoice_requested` (Phase 113-01) jest jedynym znacznikiem zadania faktury. Legacy kolumna `is_invoice` zostala usunieta w Phase 125-01 (migracja `20260513_000113_drop_orders_is_invoice_and_backfill_invoice_requested.sql`), bo dryfowala wzgledem `invoice_requested` (mapper pisal do `is_invoice`, UI czytalo `invoice_requested` — bug #1089).
 
 **order_items** — Line items within orders
 | Column | Type | Nullable | Notes |