fix: fix menu generation errors and show planned meals on home screen

Backend fixes:
- migration 003: add 'menu' value to recipe_source enum (was causing SQLSTATE 22P02)
- migration 004: rename recipe_products→recipe_ingredients, product_id→ingredient_id (was causing SQLSTATE 42P01)
- dish/repository.go: fix INSERT INTO tags using $1/$1 for two columns → $1/$2 (was causing SQLSTATE 42P08)
- home/handler.go: replace non-existent saved_recipes table with correct joins (recipes→dishes→dish_translations, user_saved_recipes) so today's plan and recommendations load correctly
- reqlog: new slog.Handler wrapper that adds request_id and stack trace to ERROR-level logs
- all handlers: slog.Error→slog.ErrorContext so error logs include request context; writeError includes request_id in response body

Client:
- home_screen.dart: extend home screen to future dates, show planned meals as ghost entries
- l10n: add new localisation keys for home screen date navigation and planned meal UI

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

backend/internal/domain/home/handler.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/food-ai/backend/internal/infra/middleware"
+	"github.com/food-ai/backend/internal/infra/locale"
 	"github.com/jackc/pgx/v5/pgxpool"
 )
 
@@ -26,7 +27,7 @@ func NewHandler(pool *pgxpool.Pool) *Handler {
 func (h *Handler) GetSummary(w http.ResponseWriter, r *http.Request) {
 	userID := middleware.UserIDFromCtx(r.Context())
 	if userID == "" {
-		writeError(w, http.StatusUnauthorized, "unauthorized")
+		writeError(w, r, http.StatusUnauthorized, "unauthorized")
 		return
 	}
 
@@ -69,7 +70,7 @@ func (h *Handler) getDailyGoal(ctx context.Context, userID string) int {
 		userID,
 	).Scan(&goal)
 	if err != nil {
-		slog.Warn("home: get daily goal", "user_id", userID, "err", err)
+		slog.WarnContext(ctx, "home: get daily goal", "user_id", userID, "err", err)
 		return 2000
 	}
 	return goal
@@ -99,21 +100,24 @@ func (h *Handler) getLoggedCalories(ctx context.Context, userID, date string) fl
 // getTodayPlan returns the three meal slots planned for today.
 // If no menu exists, all three slots are returned with nil recipe fields.
 func (h *Handler) getTodayPlan(ctx context.Context, userID, weekStart string, dow int) []MealPlan {
+	lang := locale.FromContext(ctx)
 	const q = `
 		SELECT mi.meal_type,
-		       sr.title,
-		       sr.image_url,
-		       (sr.nutrition->>'calories')::float
+		       COALESCE(dt.name, d.name) AS title,
+		       d.image_url,
+		       rec.calories_per_serving
 		FROM menu_plans mp
 		JOIN menu_items mi ON mi.menu_plan_id = mp.id
-		LEFT JOIN saved_recipes sr ON sr.id = mi.recipe_id
+		LEFT JOIN recipes rec ON rec.id = mi.recipe_id
+		LEFT JOIN dishes d ON d.id = rec.dish_id
+		LEFT JOIN dish_translations dt ON dt.dish_id = d.id AND dt.lang = $4
 		WHERE mp.user_id = $1
 		  AND mp.week_start::text = $2
 		  AND mi.day_of_week = $3`
 
-	rows, err := h.pool.Query(ctx, q, userID, weekStart, dow)
+	rows, err := h.pool.Query(ctx, q, userID, weekStart, dow, lang)
 	if err != nil {
-		slog.Warn("home: get today plan", "err", err)
+		slog.WarnContext(ctx, "home: get today plan", "err", err)
 		return defaultPlan()
 	}
 	defer rows.Close()
@@ -175,7 +179,7 @@ func (h *Handler) getExpiringSoon(ctx context.Context, userID string) []Expiring
 		userID,
 	)
 	if err != nil {
-		slog.Warn("home: get expiring soon", "err", err)
+		slog.WarnContext(ctx, "home: get expiring soon", "err", err)
 		return nil
 	}
 	defer rows.Close()
@@ -197,19 +201,25 @@ func (h *Handler) getExpiringSoon(ctx context.Context, userID string) []Expiring
 	return result
 }
 
-// getRecommendations returns the 3 most recently generated recipe recommendations.
+// getRecommendations returns the 3 most recently saved recommendation recipes.
 func (h *Handler) getRecommendations(ctx context.Context, userID string) []Recommendation {
+	lang := locale.FromContext(ctx)
 	rows, err := h.pool.Query(ctx, `
-		SELECT id, title, COALESCE(image_url, ''),
-		       (nutrition->>'calories')::float
-		FROM saved_recipes
-		WHERE user_id = $1 AND source = 'recommendation'
-		ORDER BY saved_at DESC
+		SELECT rec.id,
+		       COALESCE(dt.name, d.name),
+		       COALESCE(d.image_url, ''),
+		       rec.calories_per_serving
+		FROM user_saved_recipes usr
+		JOIN recipes rec ON rec.id = usr.recipe_id
+		JOIN dishes d ON d.id = rec.dish_id
+		LEFT JOIN dish_translations dt ON dt.dish_id = d.id AND dt.lang = $2
+		WHERE usr.user_id = $1 AND rec.source = 'recommendation'
+		ORDER BY usr.saved_at DESC
 		LIMIT 3`,
-		userID,
+		userID, lang,
 	)
 	if err != nil {
-		slog.Warn("home: get recommendations", "err", err)
+		slog.WarnContext(ctx, "home: get recommendations", "err", err)
 		return nil
 	}
 	defer rows.Close()
@@ -238,10 +248,10 @@ func mondayOfISOWeek(year, week int) time.Time {
 	return monday1.AddDate(0, 0, (week-1)*7)
 }
 
-func writeError(w http.ResponseWriter, status int, msg string) {
+func writeError(w http.ResponseWriter, r *http.Request, status int, msg string) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(status)
-	_ = json.NewEncoder(w).Encode(map[string]string{"error": msg})
+	_ = json.NewEncoder(w).Encode(map[string]any{"error": msg, "request_id": middleware.RequestIDFromCtx(r.Context())})
 }
 
 func writeJSON(w http.ResponseWriter, status int, v any) {