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/service/sensitive_service.go

@@ -4,11 +4,9 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"regexp"
 	"strings"
 	"sync"
 	"time"
-	"unicode/utf8"
 
 	"with_you/internal/model"
 	redisclient "with_you/internal/pkg/redis"
@@ -501,51 +499,3 @@ func (s *sensitiveServiceImpl) loadFromRedis(ctx context.Context) error {
 	return nil
 }
 
-// ==================== 辅助函数 ====================
-
-// ContainsSensitiveWord 快速检查文本是否包含敏感词
-func ContainsSensitiveWord(text string, tree *SensitiveWordTree) bool {
-	if tree == nil || text == "" {
-		return false
-	}
-	hasSensitive, _ := tree.Check(text)
-	return hasSensitive
-}
-
-// FilterSensitiveWords 过滤敏感词并返回替换后的文本
-func FilterSensitiveWords(text string, tree *SensitiveWordTree, repl string) string {
-	if tree == nil || text == "" {
-		return text
-	}
-	if repl == "" {
-		repl = "***"
-	}
-	return tree.Replace(text, repl)
-}
-
-// ValidateTextLength 验证文本长度是否合法
-func ValidateTextLength(text string, minLen, maxLen int) bool {
-	length := utf8.RuneCountInString(text)
-	return length >= minLen && length <= maxLen
-}
-
-// SanitizeText 清理文本，移除多余空白字符
-func SanitizeText(text string) string {
-	// 替换多个连续空白字符为单个空格
-	spaceReg := regexp.MustCompile(`\s+`)
-	text = spaceReg.ReplaceAllString(text, " ")
-	// 去除首尾空白
-	return strings.TrimSpace(text)
-}
-
-// ==================== 默认敏感词列表 ====================
-
-// DefaultSensitiveWords 返回默认敏感词列表（示例）
-func DefaultSensitiveWords() map[string]struct{} {
-	return map[string]struct{}{
-		// 示例敏感词，实际需要从数据库或配置加载
-		"测试敏感词1": {},
-		"测试敏感词2": {},
-		"测试敏感词3": {},
-	}
-}