fix: localize validation errors and polish delivery

backend/internal/handler/api/v1/conversation_handler.go

@@ -17,6 +17,7 @@ import (
 	"github.com/gochat/gochat/internal/service"
 	"github.com/gochat/gochat/pkg/pagination"
 	"github.com/gochat/gochat/pkg/response"
+	pkgvalidator "github.com/gochat/gochat/pkg/validator"
 
 	"gorm.io/datatypes"
 )
@@ -1159,6 +1160,10 @@ func handleServiceError(c *gin.Context, err error) {
 	if err == nil {
 		return
 	}
+	if pkgvalidator.IsValidationError(err) {
+		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, pkgvalidator.ValidationMessage(err))
+		return
+	}
 	errMsg := err.Error()
 	if errors.Is(err, service.ErrCaptainAssistantDisabled) {
 		response.AbortWithStatusError(c, http.StatusConflict, response.ErrCaptainAssistantDisabled, errMsg)

backend/internal/handler/api/v1/message_handler.go

@@ -18,6 +18,7 @@ import (
 	"github.com/gochat/gochat/internal/service"
 	"github.com/gochat/gochat/pkg/pagination"
 	"github.com/gochat/gochat/pkg/response"
+	pkgvalidator "github.com/gochat/gochat/pkg/validator"
 	"gorm.io/datatypes"
 )
 
@@ -388,6 +389,10 @@ func (h *MessageHandler) Translate(c *gin.Context) {
 	}
 	result, svcErr := h.svc.TranslateInConversation(c.Request.Context(), accountID, conversation.ID, messageID, req)
 	if svcErr != nil {
+		if pkgvalidator.IsValidationError(svcErr) {
+			response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, pkgvalidator.ValidationMessage(svcErr))
+			return
+		}
 		lower := strings.ToLower(svcErr.Error())
 		if strings.Contains(lower, "not found") {
 			response.AbortWithStatusError(c, http.StatusNotFound, response.ErrNotFound, svcErr.Error())