Go: add delete search (infiniflow#14014)

### What problem does this PR solve?

As title.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

Author: JinHai-CN

internal/dao/search.go

@@ -145,3 +145,18 @@ func (dao *SearchDAO) QueryByTenantIDAndID(tenantID string, searchID string) ([]
 	err := DB.Where("tenant_id = ? AND id = ? AND status = ?", tenantID, searchID, "1").Find(&searches).Error
 	return searches, err
 }
+
+// DeleteByID deletes a search by ID (soft delete by setting status to "0")
+// Reference: Python common_service.py::delete_by_id
+func (dao *SearchDAO) DeleteByID(id string) error {
+	return DB.Model(&entity.Search{}).Where("id = ?", id).Update("status", "0").Error
+}
+
+// Accessible4Deletion checks if a search can be deleted by a specific user
+// Reference: Python search_service.py::accessible4deletion
+// Returns true if the search exists, is valid, and was created by the user
+func (dao *SearchDAO) Accessible4Deletion(searchID string, userID string) bool {
+	var search entity.Search
+	err := DB.Where("id = ? AND created_by = ? AND status = ?", searchID, userID, "1").First(&search).Error
+	return err == nil
+}

internal/handler/search.go

@@ -251,3 +251,61 @@ func (h *SearchHandler) GetSearch(c *gin.Context) {
 		"message": "success",
 	})
 }
+
+// DeleteSearch delete a search app
+// @Summary Delete Search App
+// @Description Delete a search app by ID
+// @Tags search
+// @Accept json
+// @Produce json
+// @Param search_id path string true "search app ID"
+// @Success 200 {object} map[string]interface{}
+// @Router /api/v1/searches/{search_id} [delete]
+func (h *SearchHandler) DeleteSearch(c *gin.Context) {
+	// Get current user from context (same as Python current_user)
+	user, errorCode, errorMessage := GetUser(c)
+	if errorCode != common.CodeSuccess {
+		jsonError(c, errorCode, errorMessage)
+		return
+	}
+	userID := user.ID
+
+	// Get search_id from path parameter (same as Python <search_id>)
+	searchID := c.Param("search_id")
+	if searchID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"code":    common.CodeBadRequest,
+			"data":    nil,
+			"message": "search_id is required",
+		})
+		return
+	}
+
+	// Delete search with permission check
+	err := h.searchService.DeleteSearch(userID, searchID)
+	if err != nil {
+		// Check if it's an authorization error
+		if err.Error() == "no authorization" {
+			c.JSON(http.StatusOK, gin.H{
+				"code":    common.CodeAuthenticationError,
+				"data":    false,
+				"message": "No authorization.",
+			})
+			return
+		}
+		// Delete failed error
+		c.JSON(http.StatusOK, gin.H{
+			"code":    common.CodeDataError,
+			"data":    nil,
+			"message": err.Error(),
+		})
+		return
+	}
+
+	// Return success response (same as Python get_json_result(data=True))
+	c.JSON(http.StatusOK, gin.H{
+		"code":    common.CodeSuccess,
+		"data":    true,
+		"message": "success",
+	})
+}

internal/router/router.go

@@ -197,6 +197,7 @@ func (r *Router) Setup(engine *gin.Engine) {
 			searches.GET("", r.searchHandler.ListSearches)
 			searches.POST("", r.searchHandler.CreateSearch)
 			searches.GET("/:search_id", r.searchHandler.GetSearch)
+			searches.DELETE("/:search_id", r.searchHandler.DeleteSearch)
 		}
 
 			file := v1.Group("/files")

internal/service/search.go

@@ -233,3 +233,20 @@ func (s *SearchService) GetSearchDetail(userID string, searchID string) (*entity
 
 	return search, nil
 }
+
+// DeleteSearch deletes a search app by ID
+func (s *SearchService) DeleteSearch(userID string, searchID string) error {
+	// Step 1: Check deletion permission (same as Python SearchService.accessible4deletion)
+	// Python: cls.model.select().where(cls.model.id == search_id, cls.model.created_by == user_id, cls.model.status == StatusEnum.VALID.value).first()
+	if !s.searchDAO.Accessible4Deletion(searchID, userID) {
+		return fmt.Errorf("no authorization")
+	}
+
+	// Step 2: Execute delete (same as Python SearchService.delete_by_id)
+	// Python: cls.model.delete().where(cls.model.id == pid).execute()
+	if err := s.searchDAO.DeleteByID(searchID); err != nil {
+		return fmt.Errorf("failed to delete search App %s: %w", searchID, err)
+	}
+
+	return nil
+}