refactor: 文件行数超标拆解（Service + Controller 9/16 完成）

- Service 层：energy_service → energize/operations/admin/query 四文件
- Service 层：post_service → helpers/audit + 核心 CRUD 保留
- Service 层：favorite_service → items + 核心文件夹操作保留
- Service 层：auth_service → password + 核心注册/登录保留
- Service 层：notification_service → notify + 核心列表/已读保留
- Service 层：audit_service → review + 核心列表/详情保留
- Controller 层：studio_controller → page/write/api/post_api/action 五文件
- Controller 层：post_controller → page/api/upload 三文件
- Controller 层：comment_controller → list/write/action/upload 四文件
- 清理未使用导入（notification_service.go 移除 fmt）

internal/controller/comment_action_controller.go

@@ -0,0 +1,63 @@
+package controller
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+
+	"metazone.cc/metalab/internal/common"
+	"metazone.cc/metalab/internal/model"
+
+	"github.com/gin-gonic/gin"
+)
+
+// Delete DELETE /api/comments/:id
+func (ctrl *CommentController) Delete(c *gin.Context) {
+	uid, role, ok := common.GetGinUser(c)
+	if !ok {
+		common.Error(c, http.StatusUnauthorized, "请先登录")
+		return
+	}
+
+	commentID, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		common.Error(c, http.StatusBadRequest, "无效的评论ID")
+		return
+	}
+
+	// 权限检查由 service 层统一处理
+	isAdmin := model.HasMinRole(role, model.RoleAdmin)
+	if err := ctrl.commentService.Delete(uint(commentID), uid, isAdmin); err != nil {
+		if errors.Is(err, common.ErrPermissionDenied) {
+			common.Error(c, http.StatusForbidden, err.Error())
+			return
+		}
+		common.Error(c, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	common.OkMessage(c, "删除成功")
+}
+
+// SearchUsers GET /api/users/search?q=keyword
+func (ctrl *CommentController) SearchUsers(c *gin.Context) {
+	_, _, ok := common.GetGinUser(c)
+	if !ok {
+		common.Error(c, http.StatusUnauthorized, "请先登录")
+		return
+	}
+
+	q := c.Query("q")
+	if q == "" {
+		common.Ok(c, []model.UserSearchResult{})
+		return
+	}
+
+	users, err := ctrl.commentService.SearchUsers(q)
+	if err != nil {
+		common.Error(c, http.StatusInternalServerError, "搜索用户失败")
+		return
+	}
+
+	common.Ok(c, users)
+}