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/infra/reqlog/handler.go

@@ -0,0 +1,42 @@
+package reqlog
+
+import (
+	"context"
+	"log/slog"
+	"runtime/debug"
+
+	"github.com/food-ai/backend/internal/infra/middleware"
+)
+
+// Handler is a slog.Handler wrapper that enriches ERROR-level records with
+// the request_id from context and a goroutine stack trace.
+type Handler struct {
+	inner slog.Handler
+}
+
+// New wraps inner with request-aware enrichment.
+func New(inner slog.Handler) *Handler {
+	return &Handler{inner: inner}
+}
+
+func (handler *Handler) Handle(ctx context.Context, record slog.Record) error {
+	if record.Level >= slog.LevelError {
+		if requestID := middleware.RequestIDFromCtx(ctx); requestID != "" {
+			record.AddAttrs(slog.String("request_id", requestID))
+		}
+		record.AddAttrs(slog.String("stack", string(debug.Stack())))
+	}
+	return handler.inner.Handle(ctx, record)
+}
+
+func (handler *Handler) Enabled(ctx context.Context, level slog.Level) bool {
+	return handler.inner.Enabled(ctx, level)
+}
+
+func (handler *Handler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	return &Handler{inner: handler.inner.WithAttrs(attrs)}
+}
+
+func (handler *Handler) WithGroup(name string) slog.Handler {
+	return &Handler{inner: handler.inner.WithGroup(name)}
+}