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/keys.go

@@ -86,25 +86,13 @@ func ConversationListKey(userID string, page, pageSize int) string {
 	return fmt.Sprintf("%s:%s:%d:%d", PrefixConversationList, userID, page, pageSize)
 }
 
-// ConversationDetailKey 生成会话详情缓存键
-func ConversationDetailKey(conversationID, userID string) string {
-	return fmt.Sprintf("%s:%s:%s", PrefixConversationDetail, conversationID, userID)
-}
 
 // GroupMembersKey 生成群组成员缓存键
 func GroupMembersKey(groupID string, page, pageSize int) string {
 	return fmt.Sprintf("%s:%s:page:%d:size:%d", PrefixGroupMembers, groupID, page, pageSize)
 }
 
-// GroupMembersAllKey 生成群组全量成员ID列表缓存键
-func GroupMembersAllKey(groupID string) string {
-	return fmt.Sprintf("%s:all:%s", PrefixGroupMembers, groupID)
-}
 
-// GroupInfoKey 生成群组信息缓存键
-func GroupInfoKey(groupID string) string {
-	return fmt.Sprintf("%s:%s", PrefixGroupInfo, groupID)
-}
 
 // UnreadSystemKey 生成系统消息未读数缓存键
 func UnreadSystemKey(userID string) string {
@@ -121,15 +109,6 @@ func UnreadDetailKey(userID, conversationID string) string {
 	return fmt.Sprintf("%s:%s:%s", PrefixUnreadDetail, userID, conversationID)
 }
 
-// UserInfoKey 生成用户信息缓存键
-func UserInfoKey(userID string) string {
-	return fmt.Sprintf("%s:%s", PrefixUserInfo, userID)
-}
-
-// UserMeKey 生成当前用户信息缓存键
-func UserMeKey(userID string) string {
-	return fmt.Sprintf("%s:%s", PrefixUserMe, userID)
-}
 
 // ChannelsAllListKey 频道全量列表缓存键（含未启用，供 MapByIDs 解析历史帖子 channel）
 func ChannelsAllListKey() string {
@@ -156,20 +135,12 @@ func InvalidateConversationList(cache Cache, userID string) {
 	cache.DeleteByPrefix(PrefixConversationList + ":" + userID + ":")
 }
 
-// InvalidateConversationDetail 失效会话详情缓存
-func InvalidateConversationDetail(cache Cache, conversationID, userID string) {
-	cache.Delete(ConversationDetailKey(conversationID, userID))
-}
 
 // InvalidateGroupMembers 失效群组成员缓存
 func InvalidateGroupMembers(cache Cache, groupID string) {
 	cache.DeleteByPrefix(PrefixGroupMembers + ":" + groupID)
 }
 
-// InvalidateGroupInfo 失效群组信息缓存
-func InvalidateGroupInfo(cache Cache, groupID string) {
-	cache.Delete(GroupInfoKey(groupID))
-}
 
 // InvalidateUnreadSystem 失效系统消息未读数缓存
 func InvalidateUnreadSystem(cache Cache, userID string) {
@@ -186,11 +157,6 @@ func InvalidateUnreadDetail(cache Cache, userID, conversationID string) {
 	cache.Delete(UnreadDetailKey(userID, conversationID))
 }
 
-// InvalidateUserInfo 失效用户信息缓存
-func InvalidateUserInfo(cache Cache, userID string) {
-	cache.Delete(UserInfoKey(userID))
-	cache.Delete(UserMeKey(userID))
-}
 
 // ============================================================
 // 消息缓存 Key 生成函数
@@ -231,17 +197,9 @@ func MessageIdempotentKey(senderID, clientMsgID string) string {
 	return fmt.Sprintf("%s:%s:%s", keyPrefixMsgIdempotent, senderID, clientMsgID)
 }
 
-// PushDedupKey 推送去重键，防止同一消息重复推送给同一用户
-func PushDedupKey(userID, messageID string) string {
-	return fmt.Sprintf("push_dedup:%s:%s", userID, messageID)
-}
 
 // UserReadSeqKey 用户已读位置缓存键（OpenIM 风格 SEQ_USER_READ:{convID}:{userID}）
 func UserReadSeqKey(convID, userID string) string {
 	return fmt.Sprintf("%s:%s:%s", PrefixUserReadSeq, convID, userID)
 }
 
-// ConvMaxSeqKey 会话最大 seq 缓存键
-func ConvMaxSeqKey(convID string) string {
-	return fmt.Sprintf("%s:%s", keyPrefixMsgSeq, convID)
-}