feat: implement robust offline-first sync with Dexie.js

- Migrated to Dexie.js for IndexedDB management
- Added optimistic UI for tasting notes with 'Wartet auf Sync' badge
- Implemented background caching for tags and buddies
- Unified scanning and tasting sync in a global UploadQueue

src/services/save-tasting.ts

@@ -15,6 +15,7 @@ export async function saveTasting(data: {
     is_sample?: boolean;
     buddy_ids?: string[];
     tag_ids?: string[];
+    tasted_at?: string;
 }) {
     const supabase = createServerActionClient({ cookies });
 
@@ -41,6 +42,7 @@ export async function saveTasting(data: {
                 palate_notes: data.palate_notes,
                 finish_notes: data.finish_notes,
                 is_sample: data.is_sample || false,
+                created_at: data.tasted_at || undefined,
             })
             .select()
             .single();