refactor: cleanup unused code and simplify internal packages

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`.

internal/pkg/hook/hook.go

@@ -187,11 +187,6 @@ func WithAsync() HookOption {
 	}
 }
 
-func WithTimeout(timeout time.Duration) HookOption {
-	return func(h *Hook) {
-		h.Timeout = timeout
-	}
-}
 
 func (m *Manager) Trigger(ctx context.Context, hookType HookType, userID uint, data any) error {
 	return m.TriggerWithMetadata(ctx, hookType, userID, data, nil)