- Create tags table in schema with id, name (unique), createdAt
- Generate migration for tags table
- Create tag.service.ts with getAllTags (id+name, alphabetical order)
- Create tags.ts route with GET / handler
- Register /api/global-items and /api/tags routes in index.ts
- Add auth skip for GET /api/tags and GET /api/global-items
- Add globalItemId and purchasePriceCents columns to items table
- Add globalItemId column to threadCandidates table
- Add tags and globalItemTags tables for tag system
- Remove itemGlobalLinks table (replaced by direct FK)
- Generate migration with data migration step before table drop
