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/cache/layered_cache.go

@@ -2,13 +2,11 @@
 
 import (
 	"context"
-	"encoding/json"
 	"strconv"
 	"sync"
 	"time"
 
 	redislib "github.com/redis/go-redis/v9"
-	"go.uber.org/zap"
 
 	redisPkg "with_you/internal/pkg/redis"
 )
@@ -412,59 +410,6 @@ func (c *LayeredCache) GetRedisClient() *redisPkg.Client {
 	return c.redis.GetRedisClient()
 }
 
-func GetTypedLayered[T any](c *LayeredCache, key string) (T, bool) {
-	var zero T
-	if !c.enabled {
-		return zero, false
-	}
-
-	raw, ok := c.Get(key)
-	if !ok {
-		return zero, false
-	}
-
-	if typed, ok := raw.(T); ok {
-		return typed, true
-	}
-
-	if str, ok := raw.(string); ok {
-		var out T
-		if err := json.Unmarshal([]byte(str), &out); err != nil {
-			return zero, false
-		}
-		return out, true
-	}
-
-	if data, err := json.Marshal(raw); err == nil {
-		var out T
-		if err := json.Unmarshal(data, &out); err != nil {
-			return zero, false
-		}
-		return out, true
-	}
-
-	return zero, false
-}
-
-func GetOrLoadLayered[T any](
-	c *LayeredCache,
-	key string,
-	ttl time.Duration,
-	loader func() (T, error),
-) (T, error) {
-	if cached, ok := GetTypedLayered[T](c, key); ok {
-		return cached, nil
-	}
-
-	loaded, err := loader()
-	if err != nil {
-		var zero T
-		return zero, err
-	}
-
-	c.Set(key, loaded, ttl)
-	return loaded, nil
-}
 
 func (c *LayeredCache) InvalidateUserCache(userID uint) {
 	c.DeleteByPrefix(cacheKeyPrefixUser + ":")
@@ -509,15 +454,3 @@ func buildGroupMembersKey(groupID uint) string {
 }
 
 var _ Cache = (*LayeredCache)(nil)
-
-func (c *LayeredCache) logStats() {
-	stats := c.GetStats()
-	zap.L().Debug("LayeredCache stats",
-		zap.Int64("local_hits", stats.LocalHits),
-		zap.Int64("redis_hits", stats.RedisHits),
-		zap.Int64("misses", stats.Misses),
-		zap.Int64("sets", stats.Sets),
-		zap.Int64("invalidates", stats.Invalidates),
-		zap.Float64("hit_rate", c.GetHitRate()),
-	)
-}