feat: dish recognition UX, background mode, and backend bug fixes

Flutter client:
- Progress dialog: redesigned with pulsing animated icon, info hint about
  background mode, full-width Minimize button; dismiss signal via ValueNotifier
  so the dialog always closes regardless of widget lifecycle
- Background recognition: when user taps Minimize, wasMinimizedByUser flag is
  set; on completion a snackbar is shown instead of opening DishResultSheet
  directly; snackbar action opens the sheet on demand
- Fix dialog spinning forever: finally block guarantees dismissSignal=true on
  all exit paths including early returns from context.mounted checks
- Fix DishResultSheet not appearing: add ValueKey to _DailyMealsSection and
  meal card Padding so Flutter reuses elements when _TodayJobsWidget is
  inserted/removed from the SliverChildListDelegate list
- todayJobsProvider refresh: added refresh() method; called after job submit
  and on DishJobDone; all ref.read() calls guarded with context.mounted checks
- food_search_sheet: scan buttons replaced with full-width stacked OutlinedButtons
- app.dart: WidgetsBindingObserver refreshes scan providers on app resume
- L10n: added dishRecognitionHint and minimize keys to all 12 locales

Backend:
- migrations/003: ALTER TYPE recipe_source ADD VALUE 'recommendation' to fix
  22P02 error in GET /home/summary -> getRecommendations()
- item_enricher: normalizeProductCategory() validates AI-returned category
  against known slugs, falls back to "other" — fixes products_category_fkey
  FK violation during receipt recognition
- recognition prompt: enumerate valid categories so AI returns correct values

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

client/lib/features/diary/food_search_sheet.dart

@@ -220,24 +220,24 @@ class _FoodSearchSheetState extends ConsumerState<FoodSearchSheet> {
               ),
             ),
 
-            // Quick action chips
+            // Scan action buttons — full-width, stacked vertically
             Padding(
               padding: const EdgeInsets.fromLTRB(16, 8, 16, 0),
-              child: Wrap(
-                spacing: 8,
+              child: Column(
+                crossAxisAlignment: CrossAxisAlignment.stretch,
                 children: [
                   if (widget.onScanDish != null)
-                    ActionChip(
-                      avatar:
-                          const Icon(Icons.camera_alt_outlined, size: 18),
+                    OutlinedButton.icon(
+                      icon: const Icon(Icons.camera_alt_outlined, size: 18),
                       label: Text(l10n.scanDishPhoto),
                       onPressed: () {
                         Navigator.pop(context);
                         widget.onScanDish!();
                       },
                     ),
-                  ActionChip(
-                    avatar: const Icon(Icons.qr_code_scanner, size: 18),
+                  if (widget.onScanDish != null) const SizedBox(height: 8),
+                  OutlinedButton.icon(
+                    icon: const Icon(Icons.qr_code_scanner, size: 18),
                     label: Text(l10n.scanBarcode),
                     onPressed: _openBarcodeScanner,
                   ),