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/middleware/auth.go

@@ -10,7 +10,7 @@ import (
 )
 
 // Auth 认证中间件
-func Auth(jwtService *service.JWTService) gin.HandlerFunc {
+func Auth(jwtService service.JWTService) gin.HandlerFunc {
 	return func(c *gin.Context) {
 		authHeader := c.GetHeader("Authorization")
 
@@ -45,7 +45,7 @@ func Auth(jwtService *service.JWTService) gin.HandlerFunc {
 }
 
 // OptionalAuth 可选认证中间件
-func OptionalAuth(jwtService *service.JWTService) gin.HandlerFunc {
+func OptionalAuth(jwtService service.JWTService) gin.HandlerFunc {
 	return func(c *gin.Context) {
 		authHeader := c.GetHeader("Authorization")
 		if authHeader == "" {