refactor: 调整 server 目录结构

backend/internal/server/middleware/admin_only.go

@@ -0,0 +1,28 @@
+package middleware
+
+import (
+	"github.com/Wei-Shaw/sub2api/internal/model"
+
+	"github.com/gin-gonic/gin"
+)
+
+// AdminOnly 管理员权限中间件
+// 必须在JWTAuth中间件之后使用
+func AdminOnly() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		// 从上下文获取用户
+		user, exists := GetUserFromContext(c)
+		if !exists {
+			AbortWithError(c, 401, "UNAUTHORIZED", "User not found in context")
+			return
+		}
+
+		// 检查是否为管理员
+		if user.Role != model.RoleAdmin {
+			AbortWithError(c, 403, "FORBIDDEN", "Admin access required")
+			return
+		}
+
+		c.Next()
+	}
+}