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/handler/comment_handler.go

@@ -15,11 +15,11 @@ import (
 
 // CommentHandler 评论处理器
 type CommentHandler struct {
-	commentService *service.CommentService
+	commentService service.CommentService
 }
 
 // NewCommentHandler 创建评论处理器
-func NewCommentHandler(commentService *service.CommentService) *CommentHandler {
+func NewCommentHandler(commentService service.CommentService) *CommentHandler {
 	return &CommentHandler{
 		commentService: commentService,
 	}