Update COMMENT_SYSTEM_IMPLEMENTATION.md to reflect completion of Phase 2C metadata hydration work. Changes: - Updated overview status: Phase 1, 2A, 2B & 2C Complete - Updated last updated date with Phase 2C details - Added comprehensive Phase 2C implementation section (165+ lines) - Updated conclusion with Phase 2C achievements - Added Phase 2C features to key features list: - Full author metadata (handles from users table) - Community metadata (names, avatars with blob URLs) - Rich text facets (mentions, links, formatting) - Embedded content (images, quoted posts) - Content labels (NSFW, spoilers) - Updated scalability section with user batch loading stats - Added Rich Content checkmark to production readiness Documentation includes: - Batch user loading implementation details - Community name/avatar hydration with priority selection - Rich text deserialization patterns - Error handling strategies - Performance impact analysis - Lexicon compliance validation All Phase 2C work is now fully documented with technical details, implementation patterns, and production considerations. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>