fix: unify handler response format in custom_field and role handlers

- custom_field_handler.go: Fix all error responses to use {code, message}
- role_handler.go: Fix all error responses to use {code, message}

Standardize all JSON responses to {code: 0, message: "success", data: ...} for success
and {code: XXX, message: "..."} for errors.

internal/api/handler/custom_field_handler.go

@@ -23,7 +23,7 @@ func NewCustomFieldHandler(customFieldService *service.CustomFieldService) *Cust
 func (h *CustomFieldHandler) CreateField(c *gin.Context) {
 	var req service.CreateFieldRequest
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -44,13 +44,13 @@ func (h *CustomFieldHandler) CreateField(c *gin.Context) {
 func (h *CustomFieldHandler) UpdateField(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid field id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid field id"})
 		return
 	}
 
 	var req service.UpdateFieldRequest
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -71,7 +71,7 @@ func (h *CustomFieldHandler) UpdateField(c *gin.Context) {
 func (h *CustomFieldHandler) DeleteField(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid field id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid field id"})
 		return
 	}
 
@@ -90,7 +90,7 @@ func (h *CustomFieldHandler) DeleteField(c *gin.Context) {
 func (h *CustomFieldHandler) GetField(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid field id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid field id"})
 		return
 	}
 
@@ -126,7 +126,7 @@ func (h *CustomFieldHandler) ListFields(c *gin.Context) {
 func (h *CustomFieldHandler) SetUserFieldValues(c *gin.Context) {
 	userID, ok := getUserIDFromContext(c)
 	if !ok {
-		c.JSON(http.StatusUnauthorized, gin.H{"error": "unauthorized"})
+		c.JSON(http.StatusUnauthorized, gin.H{"code": 401, "message": "unauthorized"})
 		return
 	}
 
@@ -135,7 +135,7 @@ func (h *CustomFieldHandler) SetUserFieldValues(c *gin.Context) {
 	}
 
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -154,7 +154,7 @@ func (h *CustomFieldHandler) SetUserFieldValues(c *gin.Context) {
 func (h *CustomFieldHandler) GetUserFieldValues(c *gin.Context) {
 	userID, ok := getUserIDFromContext(c)
 	if !ok {
-		c.JSON(http.StatusUnauthorized, gin.H{"error": "unauthorized"})
+		c.JSON(http.StatusUnauthorized, gin.H{"code": 401, "message": "unauthorized"})
 		return
 	}
 

internal/api/handler/role_handler.go

@@ -23,7 +23,7 @@ func NewRoleHandler(roleService *service.RoleService) *RoleHandler {
 func (h *RoleHandler) CreateRole(c *gin.Context) {
 	var req service.CreateRoleRequest
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -43,7 +43,7 @@ func (h *RoleHandler) CreateRole(c *gin.Context) {
 func (h *RoleHandler) ListRoles(c *gin.Context) {
 	var req service.ListRoleRequest
 	if err := c.ShouldBindQuery(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -54,11 +54,11 @@ func (h *RoleHandler) ListRoles(c *gin.Context) {
 	}
 
 	c.JSON(http.StatusOK, gin.H{
-		"code": 0,
+		"code":    0,
 		"message": "success",
 		"data": gin.H{
 			"items": roles,
-			"total":  total,
+			"total": total,
 		},
 	})
 }
@@ -66,7 +66,7 @@ func (h *RoleHandler) ListRoles(c *gin.Context) {
 func (h *RoleHandler) GetRole(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid role id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid role id"})
 		return
 	}
 
@@ -86,13 +86,13 @@ func (h *RoleHandler) GetRole(c *gin.Context) {
 func (h *RoleHandler) UpdateRole(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid role id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid role id"})
 		return
 	}
 
 	var req service.UpdateRoleRequest
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -112,7 +112,7 @@ func (h *RoleHandler) UpdateRole(c *gin.Context) {
 func (h *RoleHandler) DeleteRole(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid role id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid role id"})
 		return
 	}
 
@@ -130,7 +130,7 @@ func (h *RoleHandler) DeleteRole(c *gin.Context) {
 func (h *RoleHandler) UpdateRoleStatus(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid role id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid role id"})
 		return
 	}
 
@@ -139,7 +139,7 @@ func (h *RoleHandler) UpdateRoleStatus(c *gin.Context) {
 	}
 
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}
 
@@ -150,7 +150,7 @@ func (h *RoleHandler) UpdateRoleStatus(c *gin.Context) {
 	case "disabled", "0":
 		status = domain.RoleStatusDisabled
 	default:
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid status"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid status"})
 		return
 	}
 
@@ -169,7 +169,7 @@ func (h *RoleHandler) UpdateRoleStatus(c *gin.Context) {
 func (h *RoleHandler) GetRolePermissions(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid role id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid role id"})
 		return
 	}
 
@@ -189,7 +189,7 @@ func (h *RoleHandler) GetRolePermissions(c *gin.Context) {
 func (h *RoleHandler) AssignPermissions(c *gin.Context) {
 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
 	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid role id"})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "invalid role id"})
 		return
 	}
 
@@ -198,7 +198,7 @@ func (h *RoleHandler) AssignPermissions(c *gin.Context) {
 	}
 
 	if err := c.ShouldBindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": err.Error()})
 		return
 	}