refactor(server): decouple services and improve architecture

- Introduce interfaces for all major services (JWT, PostAI, Comment, Message, Notification, QRCodeLogin, Upload, Vote, etc.) to support dependency inversion.
- Move query parameters from `internal/dto` to a new `internal/query` package to separate request payloads from data transfer objects.
- Refactor `internal/router` to use embedded `RouterDeps` for cleaner dependency management.
- Decouple handlers from repositories by injecting services instead of direct repository access, ensuring proper layering.
- Improve database initialization by moving it from `internal/model` to `internal/database`.
- Optimize message decryption by implementing a more efficient `BatchDecrypt` method in `MessageEncryptor` using a worker pool.
- Enhance error handling and security by implementing fail-fast checks for encryption key length during startup.
- Clean up unused code, including the `avatar` package and several unused DTOs.

internal/service/qrcode_login_service.go

@@ -51,19 +51,30 @@ type QRCodeSession struct {
 	ExpiresAt int64        `json:"expires_at"`
 }
 
-// QRCodeLoginService 二维码登录服务
-type QRCodeLoginService struct {
+// QRCodeLoginService 二维码登录服务接口
+type QRCodeLoginService interface {
+	CreateSession(ctx context.Context) (*QRCodeSession, error)
+	GetSession(ctx context.Context, sessionID string) (*QRCodeSession, error)
+	Scan(ctx context.Context, sessionID, userID string) error
+	Confirm(ctx context.Context, sessionID, userID string, ip, userAgent string) (*LoginResponse, error)
+	Cancel(ctx context.Context, sessionID, userID string) error
+	GetWSHub() *ws.Hub
+	GetUserService() UserService
+}
+
+// qrcodeLoginService 二维码登录服务实现
+type qrcodeLoginService struct {
 	redis           *redis.Client
 	wsHub           ws.MessagePublisher
-	jwtService      *JWTService
+	jwtService      JWTService
 	userService     UserService
 	activityService UserActivityService
 	logService      *LogService
 }
 
 // NewQRCodeLoginService 创建二维码登录服务
-func NewQRCodeLoginService(redis *redis.Client, publisher ws.MessagePublisher, jwtService *JWTService, userService UserService, activityService UserActivityService, logService *LogService) *QRCodeLoginService {
-	return &QRCodeLoginService{
+func NewQRCodeLoginService(redis *redis.Client, publisher ws.MessagePublisher, jwtService JWTService, userService UserService, activityService UserActivityService, logService *LogService) QRCodeLoginService {
+	return &qrcodeLoginService{
 		redis:           redis,
 		wsHub:           publisher,
 		jwtService:      jwtService,
@@ -74,7 +85,7 @@ func NewQRCodeLoginService(redis *redis.Client, publisher ws.MessagePublisher, j
 }
 
 // CreateSession 创建二维码会话
-func (s *QRCodeLoginService) CreateSession(ctx context.Context) (*QRCodeSession, error) {
+func (s *qrcodeLoginService) CreateSession(ctx context.Context) (*QRCodeSession, error) {
 	sessionID := uuid.New().String()
 	now := time.Now()
 	expiresAt := now.Add(qrcodeSessionTTL)
@@ -106,7 +117,7 @@ func (s *QRCodeLoginService) CreateSession(ctx context.Context) (*QRCodeSession,
 }
 
 // GetSession 获取会话
-func (s *QRCodeLoginService) GetSession(ctx context.Context, sessionID string) (*QRCodeSession, error) {
+func (s *qrcodeLoginService) GetSession(ctx context.Context, sessionID string) (*QRCodeSession, error) {
 	key := qrcodeSessionPrefix + sessionID
 	data, err := s.redis.HGetAll(ctx, key)
 	if err != nil {
@@ -140,7 +151,7 @@ func (s *QRCodeLoginService) GetSession(ctx context.Context, sessionID string) (
 }
 
 // Scan 扫描二维码
-func (s *QRCodeLoginService) Scan(ctx context.Context, sessionID, userID string) error {
+func (s *qrcodeLoginService) Scan(ctx context.Context, sessionID, userID string) error {
 	key := qrcodeSessionPrefix + sessionID
 
 	// 使用 Lua 脚本实现原子性检查和更新，避免竞态条件
@@ -176,7 +187,7 @@ func (s *QRCodeLoginService) Scan(ctx context.Context, sessionID, userID string)
 }
 
 // Confirm 确认登录
-func (s *QRCodeLoginService) Confirm(ctx context.Context, sessionID, userID string, ip, userAgent string) (*LoginResponse, error) {
+func (s *qrcodeLoginService) Confirm(ctx context.Context, sessionID, userID string, ip, userAgent string) (*LoginResponse, error) {
 	session, err := s.GetSession(ctx, sessionID)
 	if err != nil {
 		return nil, err
@@ -255,7 +266,7 @@ type LoginResponse struct {
 }
 
 // Cancel 取消登录
-func (s *QRCodeLoginService) Cancel(ctx context.Context, sessionID, userID string) error {
+func (s *qrcodeLoginService) Cancel(ctx context.Context, sessionID, userID string) error {
 	session, err := s.GetSession(ctx, sessionID)
 	if err != nil {
 		return err
@@ -281,7 +292,7 @@ func (s *QRCodeLoginService) Cancel(ctx context.Context, sessionID, userID strin
 }
 
 // GetWSHub 获取底层 WS Hub（用于 Subscribe 等本地操作）
-func (s *QRCodeLoginService) GetWSHub() *ws.Hub {
+func (s *qrcodeLoginService) GetWSHub() *ws.Hub {
 	switch p := s.wsHub.(type) {
 	case *ws.Bus:
 		return p.Hub()
@@ -293,6 +304,6 @@ func (s *QRCodeLoginService) GetWSHub() *ws.Hub {
 }
 
 // GetUserService 获取用户服务
-func (s *QRCodeLoginService) GetUserService() UserService {
+func (s *qrcodeLoginService) GetUserService() UserService {
 	return s.userService
 }