Fix billing data integrity, sale atomicity and stock safety

Bills were persisted correctly but read back wrong. The read path rebuilt a
cart from its lines alone, dropping bill-level discounts and loyalty, so every
figure derived from a stored bill was overstated: the upload payload, the day
archive and the shift report. A discounted 529 bill read back as 620.

Money and data integrity
- order_dao: restore bill_discount and points_redeemed when rebuilding a cart;
  keep the reconstruction tier-less so the membership discount is not applied
  twice. Trust the recorded total and points via SaleTransaction.storedTotal.
- checkout_sale + order_dao.commitSale: write the bill, its stock movement and
  the loyalty update in one transaction. Previously a failure part-way through
  left a persisted bill the cashier believed had failed, inviting a duplicate.
- checkout_sale: re-check every line against live stock. A parked bill resumed
  after its stock was sold passed validation and oversold.
- catalogue_dao: allocate the invoice sequence in one transaction; the previous
  read-modify-write could hand two sales the same number and fail UNIQUE.
- local_store: replay unsynced sales after a catalogue import, so a mid-shift
  re-import cannot restore stock that has already been sold.
- payment_controller: stamp the signed-in operator on the bill instead of the
  hardcoded seed session, and pass the terminal id through.
- cart: reconcile per-slab GST against the bill total so the parts sum to the
  whole on a tax invoice.

Sync and reporting
- sync_repository: drain unsynced bills in a loop rather than silently capping
  at one page; stop on rejection so rejected rows cannot loop forever.
- sync_log_dao (new): persist the sync history to the sync_log table, which the
  schema already defined but nothing used. It was in memory, so the only record
  that bills had been uploaded died at restart.
- Scope shift reports by cashier. day_archive is re-keyed to
  (business_date, cashier_name) so a till stays settleable after its bills are
  uploaded and deleted. Schema v4 with a migration that carries v3 rows across.

Input and UI
- barcode_service: consume machine-paced keystrokes so a scan cannot also land
  in the focused field, and raise the bar to 60ms/char while a text field has
  focus so typing a mobile number is not read as a scan. Clock and focus check
  injected so the behaviour is testable.
- primary_button: make the label flexible; label plus trailing total overflowed
  the Charge button by up to 131px.
- app_router: redirect instead of null-casting when the receipt route is
  entered without its transaction.
- customer_repository: reduce the search query to digits so a punctuated mobile
  number matches.

Cleanup
- Remove TransactionRepository.save, CustomerRepository.recordSale and
  OrderDao.insertOrder, all superseded by commitSale.
- dart fix across the tree; 251 analyzer issues down to 3 info-level.

Tests: 23 passing / 15 failing -> 90 passing. Fixed the two defects that broke
the existing suite (containsAll type argument, reset() needing a catalogue) and
deleted the leftover template test. Added coverage for the order round trip,
the day archive after a real sync, stock safety, checkout atomicity, the v3->v4
migration, scanner-versus-human input, and an app-level smoke test that renders
every module.

Note: bills already uploaded with a discount went up overstated. This stops it
happening again but does not correct historical server data.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

lib/presentation/pos/screens/pos_dashboard_screen.dart

@@ -13,6 +13,7 @@ import '../../modules/screens/promos_view.dart';
 import '../../modules/screens/settings_view.dart';
 import '../../sync/providers/sync_controller.dart';
 import '../providers/cart_controller.dart';
+import '../providers/catalog_providers.dart';
 import '../providers/navigation_provider.dart';
 import '../widgets/app_sidebar.dart';
 import '../widgets/billing_panel.dart';
@@ -56,6 +57,9 @@ class _PosDashboardScreenState extends ConsumerState<PosDashboardScreen> {
         // Without an imported catalogue there is nothing to resolve against.
         if (!ref.read(catalogueReadyProvider)) return;
         ref.read(activeModuleProvider.notifier).state = PosModule.pos;
+        // Drop any character the burst leaked into the search box before the
+        // scan was recognised, so the grid is not left filtered to nothing.
+        ref.read(searchQueryProvider.notifier).state = '';
         ref.read(cartControllerProvider.notifier).scanBarcode(code);
       },
     )..attach();
@@ -73,13 +77,13 @@ class _PosDashboardScreenState extends ConsumerState<PosDashboardScreen> {
       context: context,
       isScrollControlled: true,
       backgroundColor: Colors.transparent,
-      builder: (_) => FractionallySizedBox(
+      builder: (_) => const FractionallySizedBox(
         heightFactor: 0.92,
         child: ClipRRect(
-          borderRadius: const BorderRadius.vertical(
+          borderRadius: BorderRadius.vertical(
             top: Radius.circular(AppRadius.xxl),
           ),
-          child: const BillingPanel(inSheet: true),
+          child: BillingPanel(inSheet: true),
         ),
       ),
     );

lib/presentation/pos/screens/pos_view.dart

@@ -98,7 +98,7 @@ class _CatalogueRequired extends ConsumerWidget {
                   shape: BoxShape.circle,
                 ),
                 child: const Icon(Icons.cloud_download_outlined,
-                    size: 42, color: AppColors.primary),
+                    size: 42, color: AppColors.primary,),
               ),
               const SizedBox(height: AppSpacing.xxl),
               Text(
@@ -136,7 +136,7 @@ class _CatalogueRequired extends ConsumerWidget {
                     minHeight: 8,
                     backgroundColor: AppColors.divider,
                     valueColor: const AlwaysStoppedAnimation<Color>(
-                        AppColors.primary),
+                        AppColors.primary,),
                   ),
                 ),
                 const SizedBox(height: AppSpacing.lg),
@@ -146,7 +146,7 @@ class _CatalogueRequired extends ConsumerWidget {
                 Container(
                   padding: const EdgeInsets.all(AppSpacing.md),
                   margin: const EdgeInsets.only(bottom: AppSpacing.lg),
-                  decoration: BoxDecoration(
+                  decoration: const BoxDecoration(
                     color: AppColors.dangerSurface,
                     borderRadius: AppRadius.brSm,
                   ),
@@ -154,7 +154,7 @@ class _CatalogueRequired extends ConsumerWidget {
                     crossAxisAlignment: CrossAxisAlignment.start,
                     children: [
                       const Icon(Icons.wifi_off_rounded,
-                          color: AppColors.danger, size: 18),
+                          color: AppColors.danger, size: 18,),
                       const SizedBox(width: AppSpacing.sm),
                       Expanded(
                         child: Text(