feat: improved receipt recognition, batch product add, and scan UX

- Rewrite receipt OCR prompt: completes truncated names, preserves fat%
  and flavour attributes, extracts weight/volume from line, infers
  typical package sizes for solid goods with quantity_confidence field
- Add quantity_confidence to RecognizedItem, EnrichedItem, and
  ProductJobResultItem; propagate through item enricher and worker
- Replace per-item create loop with single POST /user-products/batch call
  from RecognitionConfirmScreen
- Rebuild RecognitionConfirmScreen: amber qty border for low
  quantity_confidence, tappable product name → catalog picker,
  sort items by confidence, full L10n (no hardcoded strings)
- Add timestamps (HH:mm / d MMM HH:mm) to recent scan chips
- Show close-app hint on ProductJobWatchScreen (queued + processing)
- Refresh recentProductJobsProvider on watch screen init so new job
  appears without a manual pull-to-refresh
- App-level WidgetsBindingObserver refreshes product and dish job lists
  on resume, fixing stale lists after background/foreground transitions
- Add 9 new L10n keys across all 12 locales

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/lib/features/products/products_screen.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
+import 'package:intl/intl.dart';
 
 import '../../core/locale/unit_provider.dart';
 import '../../l10n/app_localizations.dart';
@@ -120,7 +121,7 @@ class _RecentScansSection extends ConsumerWidget {
           ),
         ),
         SizedBox(
-          height: 72,
+          height: 84,
           child: ListView.builder(
             scrollDirection: Axis.horizontal,
             padding: const EdgeInsets.symmetric(horizontal: 12),
@@ -187,6 +188,12 @@ class _ScanJobChip extends ConsumerWidget {
                     isFailed: isFailed,
                     isActive: isActive,
                   ),
+                  Text(
+                    _formatChipDate(job.createdAt),
+                    style: theme.textTheme.labelSmall?.copyWith(
+                      color: theme.colorScheme.onSurfaceVariant,
+                    ),
+                  ),
                 ],
               ),
             ],
@@ -197,6 +204,17 @@ class _ScanJobChip extends ConsumerWidget {
   }
 }
 
+String _formatChipDate(DateTime dateTime) {
+  final local = dateTime.toLocal();
+  final now = DateTime.now();
+  final isToday = local.year == now.year &&
+      local.month == now.month &&
+      local.day == now.day;
+  return isToday
+      ? DateFormat.Hm().format(local)
+      : DateFormat('d MMM HH:mm').format(local);
+}
+
 class _StatusBadge extends StatelessWidget {
   const _StatusBadge({
     required this.status,

client/lib/features/products/user_product_provider.dart

@@ -72,6 +72,17 @@ class UserProductsNotifier
     });
   }
 
+  /// Adds multiple products in a single request and appends them to the list.
+  Future<void> batchCreate(List<Map<String, dynamic>> payloads) async {
+    final created = await _service.batchCreateProducts(payloads);
+    state.whenData((products) {
+      final updated = [...products, ...created]
+        ..sort((firstProduct, secondProduct) =>
+            firstProduct.expiresAt.compareTo(secondProduct.expiresAt));
+      state = AsyncValue.data(updated);
+    });
+  }
+
   /// Updates a product in-place, keeping list sort order.
   Future<void> update(
     String id, {

client/lib/features/products/user_product_service.dart

@@ -61,6 +61,14 @@ class UserProductService {
     return UserProduct.fromJson(data);
   }
 
+  Future<List<UserProduct>> batchCreateProducts(
+      List<Map<String, dynamic>> payloads) async {
+    final list = await _client.postList('/user-products/batch', data: payloads);
+    return list
+        .map((element) => UserProduct.fromJson(element as Map<String, dynamic>))
+        .toList();
+  }
+
   Future<void> deleteProduct(String id) =>
       _client.deleteVoid('/user-products/$id');