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/casbin.go

@@ -9,63 +9,6 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
-// CasbinAuth Casbin 权限中间件
-// 需要在 Auth 中间件之后使用
-func CasbinAuth(casbinService service.CasbinService) gin.HandlerFunc {
-	return func(c *gin.Context) {
-		// 获取请求路径和方法
-		path := c.Request.URL.Path
-		method := c.Request.Method
-
-		// 从上下文获取用户ID (由 Auth 中间件设置)
-		userID, exists := c.Get("user_id")
-
-		// 如果用户未登录，检查是否是公开路由
-		if !exists {
-			// 对于未登录用户，使用匿名角色检查权限
-			allowed, err := casbinService.Enforce(c.Request.Context(), "anonymous", path, method)
-			if err != nil {
-				c.AbortWithStatusJSON(500, gin.H{
-					"code":    "INTERNAL_ERROR",
-					"message": "权限检查失败",
-				})
-				return
-			}
-
-			if !allowed {
-				c.AbortWithStatusJSON(401, gin.H{
-					"code":    "UNAUTHORIZED",
-					"message": "请先登录",
-				})
-				return
-			}
-
-			c.Next()
-			return
-		}
-
-		// 检查用户权限
-		allowed, err := casbinService.EnforceForUser(c.Request.Context(), userID.(string), path, method)
-		if err != nil {
-			c.AbortWithStatusJSON(500, gin.H{
-				"code":    "INTERNAL_ERROR",
-				"message": "权限检查失败",
-			})
-			return
-		}
-
-		if !allowed {
-			c.AbortWithStatusJSON(403, gin.H{
-				"code":    "FORBIDDEN",
-				"message": "权限不足",
-			})
-			return
-		}
-
-		c.Next()
-	}
-}
-
 // RequireRole 要求特定角色的中间件
 func RequireRole(casbinService service.CasbinService, requiredRoles ...string) gin.HandlerFunc {
 	return func(c *gin.Context) {