- Add `tags` field to AddonInfo model with serialization support
- Add `_load_repo_tags()` to CacheScraper to read tags from addon files
- Populate 160 addon files with curated tags using 8 categories:
ai, metadata, reader, notes, attachment, interface, integration, utility
- Add test cases for tags field in AddonInfo model
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>