feat: slim meal_diary — derive name and nutrition from dish/recipe

Remove denormalized columns (name, calories, protein_g, fat_g, carbs_g)
from meal_diary. Name is now resolved via JOIN with dishes/dish_translations;
macros are computed as recipe.*_per_serving * portions at query time.

- Add dish.Repository.FindOrCreateRecipe: finds or creates a minimal recipe
  stub seeded with AI-estimated macros
- recognition/handler: resolve recipe_id synchronously per candidate;
  simplify enrichDishInBackground to translations-only
- diary/handler: accept dish_id OR name; always resolve recipe_id via
  FindOrCreateRecipe before INSERT
- diary/entity: DishID is now non-nullable string; CreateRequest drops macros
- diary/repository: ListByDate and Create use JOIN to return computed macros
- ai/types: add RecipeID field to DishCandidate
- Update tests and wire_gen accordingly

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

client/lib/features/scan/dish_result_screen.dart

@@ -106,6 +106,7 @@ class _DishResultSheetState extends ConsumerState<DishResultSheet> {
         'carbs_g': scaledCarbs,
         'portion_g': _portionGrams,
         'source': 'recognition',
+        if (_selected.dishId != null) 'dish_id': _selected.dishId,
       });
       if (mounted) widget.onAdded();
     } catch (addError) {