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/l10n/app_localizations.dart

@@ -1161,6 +1161,60 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Added to pantry'**
   String get productAddedToShelf;
+
+  /// No description provided for @recognitionFoundProducts.
+  ///
+  /// In en, this message translates to:
+  /// **'Found {count} products'**
+  String recognitionFoundProducts(int count);
+
+  /// No description provided for @recognitionAddAll.
+  ///
+  /// In en, this message translates to:
+  /// **'Add all'**
+  String get recognitionAddAll;
+
+  /// No description provided for @recognitionAddToStock.
+  ///
+  /// In en, this message translates to:
+  /// **'Add to pantry'**
+  String get recognitionAddToStock;
+
+  /// No description provided for @recognitionAdded.
+  ///
+  /// In en, this message translates to:
+  /// **'Added {count} products'**
+  String recognitionAdded(int count);
+
+  /// No description provided for @recognitionProductsFailed.
+  ///
+  /// In en, this message translates to:
+  /// **'Failed to add products'**
+  String get recognitionProductsFailed;
+
+  /// No description provided for @recognitionEmpty.
+  ///
+  /// In en, this message translates to:
+  /// **'No products found'**
+  String get recognitionEmpty;
+
+  /// No description provided for @recognitionConfidence.
+  ///
+  /// In en, this message translates to:
+  /// **'{percent}% confidence'**
+  String recognitionConfidence(int percent);
+
+  /// No description provided for @recognitionReplaceProduct.
+  ///
+  /// In en, this message translates to:
+  /// **'Replace product'**
+  String get recognitionReplaceProduct;
+
+  /// No description provided for @scanJobCloseHint.
+  ///
+  /// In en, this message translates to:
+  /// **'You can close the app — this scan will appear in Recent Scans on the Products screen'**
+  String get scanJobCloseHint;
 }
 
 class _AppLocalizationsDelegate