feat: implement AI custom tag proposals

- AI now suggests dominant notes not in the system list (Part 3: Custom Suggestions)
- Updated TagSelector to show 'Neu anlegen?' buttons for AI-proposed custom tags
- Added suggested_custom_tags to bottles table and metadata schema
- Updated TastingNoteForm to handle both system and custom AI suggestions

src/types/whisky.ts

@@ -14,6 +14,8 @@ export const BottleMetadataSchema = z.object({
     batch_info: z.string().nullish(),
     is_whisky: z.boolean().default(true),
     confidence: z.number().min(0).max(100).default(100),
+    suggested_tags: z.array(z.string()).nullish(),
+    suggested_custom_tags: z.array(z.string()).nullish(),
 });
 
 export type BottleMetadata = z.infer<typeof BottleMetadataSchema>;