feat: meal tracking, dish recognition UX improvements, English AI prompts

Backend:
- Translate all recognition prompts (receipt, products, dish) from Russian to English
- Add lang parameter to Recognizer interface and pass locale.FromContext in handlers
- DishResult type uses candidates array for multi-candidate responses

Client:
- Add meal tracking: diary provider, date selector, meal type model
- DishResult parser: backward-compatible with legacy flat format and new candidates format
- DishResultScreen: sticky bottom button, full-width portion/meal-type inputs,
  КБЖУ disclaimer moved under nutrition card, add date field to diary POST body
- Recognition prompts now return dish/product names in user's preferred language
- Onboarding, profile, home screen visual updates

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

client/lib/features/onboarding/onboarding_screen.dart

@@ -4,10 +4,11 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../core/theme/app_colors.dart';
+import '../../shared/models/meal_type.dart';
 import '../profile/profile_provider.dart';
 import '../profile/profile_service.dart';
 
-const int _totalSteps = 6;
+const int _totalSteps = 7;
 
 const List<Color> _stepAccentColors = [
   Color(0xFF5856D6), // Goal — iOS purple
@@ -15,6 +16,7 @@ const List<Color> _stepAccentColors = [
   Color(0xFFFF9500), // DOB — iOS orange
   Color(0xFF34C759), // Height + Weight — iOS green
   Color(0xFFFF2D55), // Activity — iOS pink
+  Color(0xFF30B0C7), // Meal Types — teal
   Color(0xFFFF6B00), // Calories — deep orange
 ];
 
@@ -24,6 +26,7 @@ const List<IconData> _stepIcons = [
   Icons.cake_outlined,
   Icons.monitor_weight_outlined,
   Icons.directions_run,
+  Icons.restaurant_menu,
   Icons.local_fire_department,
 ];
 
@@ -45,6 +48,7 @@ class _OnboardingScreenState extends ConsumerState<OnboardingScreen> {
   final _heightController = TextEditingController();
   final _weightController = TextEditingController();
   String? _activity;
+  List<String> _mealTypes = List<String>.from(kDefaultMealTypeIds);
   int _dailyCalories = 2000;
 
   bool _saving = false;
@@ -116,7 +120,9 @@ class _OnboardingScreenState extends ConsumerState<OnboardingScreen> {
             weightValue <= 300;
       case 4: // Activity
         return _activity != null;
-      case 5: // Calories
+      case 5: // Meal Types — at least one must be selected
+        return _mealTypes.isNotEmpty;
+      case 6: // Calories
         return true;
       default:
         return false;
@@ -127,7 +133,7 @@ class _OnboardingScreenState extends ConsumerState<OnboardingScreen> {
     if (!_canAdvance()) return;
 
     // Entering calorie review — pre-calculate based on collected data
-    if (_currentStep == 4) {
+    if (_currentStep == 5) {
       setState(() => _dailyCalories = _calculateCalories());
     }
 
@@ -166,6 +172,7 @@ class _OnboardingScreenState extends ConsumerState<OnboardingScreen> {
       gender: _gender,
       goal: _goal,
       activity: _activity,
+      mealTypes: _mealTypes,
       dailyCalories: _dailyCalories,
     );
 
@@ -257,9 +264,19 @@ class _OnboardingScreenState extends ConsumerState<OnboardingScreen> {
                   _StepPage(
                     accentColor: _stepAccentColors[5],
                     icon: _stepIcons[5],
+                    child: _MealTypesStepContent(
+                      selected: _mealTypes,
+                      accentColor: _stepAccentColors[5],
+                      onChanged: (updated) =>
+                          setState(() => _mealTypes = updated),
+                    ),
+                  ),
+                  _StepPage(
+                    accentColor: _stepAccentColors[6],
+                    icon: _stepIcons[6],
                     child: _CalorieStepContent(
                       calories: _dailyCalories,
-                      accentColor: _stepAccentColors[5],
+                      accentColor: _stepAccentColors[6],
                       onChanged: (value) =>
                           setState(() => _dailyCalories = value),
                     ),
@@ -1108,7 +1125,83 @@ class _ActivityCard extends StatelessWidget {
   }
 }
 
-// ── Step 6: Calorie review ─────────────────────────────────────
+// ── Step 6: Meal types ─────────────────────────────────────────
+
+class _MealTypesStepContent extends StatelessWidget {
+  final List<String> selected;
+  final Color accentColor;
+  final ValueChanged<List<String>> onChanged;
+
+  const _MealTypesStepContent({
+    required this.selected,
+    required this.accentColor,
+    required this.onChanged,
+  });
+
+  void _toggle(String mealTypeId) {
+    final updated = List<String>.from(selected);
+    if (updated.contains(mealTypeId)) {
+      // Keep at least one meal type selected.
+      if (updated.length > 1) updated.remove(mealTypeId);
+    } else {
+      updated.add(mealTypeId);
+    }
+    onChanged(updated);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        Text('Ваши приёмы пищи', style: theme.textTheme.headlineSmall),
+        const SizedBox(height: 4),
+        Text(
+          'Выберите, какие приёмы пищи вы хотите отслеживать',
+          style: theme.textTheme.bodyMedium
+              ?.copyWith(color: AppColors.textSecondary),
+        ),
+        const SizedBox(height: 20),
+        ...kAllMealTypes.map((mealTypeOption) {
+          final isSelected = selected.contains(mealTypeOption.id);
+          return Padding(
+            padding: const EdgeInsets.only(bottom: 10),
+            child: _SelectableCard(
+              selected: isSelected,
+              accentColor: accentColor,
+              onTap: () => _toggle(mealTypeOption.id),
+              child: Row(
+                children: [
+                  Text(mealTypeOption.emoji,
+                      style: const TextStyle(fontSize: 24)),
+                  const SizedBox(width: 12),
+                  Expanded(
+                    child: Text(
+                      mealTypeOption.label,
+                      style: theme.textTheme.bodyLarge?.copyWith(
+                        color: isSelected
+                            ? accentColor
+                            : AppColors.textPrimary,
+                        fontWeight: isSelected
+                            ? FontWeight.w600
+                            : FontWeight.normal,
+                      ),
+                    ),
+                  ),
+                  if (isSelected)
+                    Icon(Icons.check_circle, color: accentColor),
+                ],
+              ),
+            ),
+          );
+        }),
+      ],
+    );
+  }
+}
+
+// ── Step 7: Calorie review ─────────────────────────────────────
 
 class _CalorieStepContent extends StatelessWidget {
   final int calories;