The moderation system now uses a "pass/review" strategy instead of "pass/review/block", treating hard violations the same as review (only routing to manual review rather than auto-rejecting). Add fallback-approve behavior in the hook system so slow moderation APIs never silently block normal content when they time out or get cancelled - timed-out moderation now approves with "ReviewedBy: system" instead of leaving the zero-value result that would reject content. Update post/comment/vote services and handlers to use the new unified behavior. Simplify moderation prompts to emphasize "宁可放过，不可误伤" (prefer false positives over false negatives).
This commit performs a significant cleanup of the codebase by removing unused functions, methods, and entire files across various internal modules. This reduces technical debt and simplifies the project structure.
Key changes include:
- **cache**: Removed unused cache key generators and metrics snapshots.
- **dto**: Removed redundant converter functions and segment creation helpers.
- **middleware**: Deleted the unused `logger.go` middleware and simplified `ratelimit.go` and `casbin.go`.
- **model**: Removed unused ID helpers, database closing functions, and batch decryption logic.
- **pkg**: Cleaned up unused utility functions in `circuitbreaker`, `crypto`, `cursor`, `hook`, and `utils`.
- **service**: Deleted `account_cleanup_service.go` and removed unused helper functions in `log_cleanup_service.go` and `sensitive_service.go`.
- **repository**: Removed unused private loading methods in `comment_repo.go`.
- Implement extensible hook system for content moderation with
builtin and AI-powered moderation hooks
- Add QR code login feature with SSE for real-time status updates
and scan/confirm/cancel workflow
- Introduce layered cache with local LRU + Redis backend for
improved read performance
- Refactor post and comment services to use hook-based moderation
instead of direct AI service calls
- Add local cache configuration options (size, buckets, ttl)
