feat(conversations): align custom attribute response

internal/handler/api/v1/conversation_handler.go

@@ -746,7 +746,7 @@ func (h *ConversationHandler) UpdateCustomAttributes(c *gin.Context) {
 		return
 	}
 
-	c.JSON(http.StatusOK, gin.H{"custom_attributes": conversation.CustomAttributes})
+	c.JSON(http.StatusOK, gin.H{"custom_attributes": jsonObject(conversation.CustomAttributes)})
 }
 
 // ListAttachments returns paginated message attachments for a conversation.

internal/handler/api/v1/conversation_handler_test.go

@@ -338,6 +338,28 @@ func (s *ConversationHandlerTestSuite) TestUpdateCustomAttributes_Success() {
 	assert.NoError(s.T(), err)
 	assert.NotContains(s.T(), rawResp, "id")
 	assert.NotContains(s.T(), rawResp, "success")
+	assert.NotContains(s.T(), rawResp, "payload")
+	assert.NotContains(s.T(), rawResp, "meta")
+}
+
+func (s *ConversationHandlerTestSuite) TestUpdateCustomAttributes_EmptyObjectReturnsChatwootShape() {
+	body := map[string]interface{}{
+		"custom_attributes": map[string]interface{}{},
+	}
+	bodyBytes, _ := json.Marshal(body)
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest("POST", s.accountURL()+"/conversations/"+strconv.FormatUint(uint64(s.testConv.ID), 10)+"/custom_attributes", bytes.NewReader(bodyBytes))
+	req.Header.Set("Content-Type", "application/json")
+	s.router.ServeHTTP(w, req)
+
+	assert.Equal(s.T(), http.StatusOK, w.Code)
+
+	var rawResp map[string]interface{}
+	err := json.Unmarshal(w.Body.Bytes(), &rawResp)
+	assert.NoError(s.T(), err)
+	assert.Equal(s.T(), map[string]interface{}{}, rawResp["custom_attributes"])
+	assert.Len(s.T(), rawResp, 1)
 }
 
 func (s *ConversationHandlerTestSuite) TestUpdateCustomAttributes_InvalidAccountID() {