i18n and UI fix

src/main/kintone-api.ts

@@ -8,6 +8,7 @@ import {
   type KintoneApiError,
   AppCustomizeParameter,
 } from "@shared/types/kintone";
+import { getErrorMessage } from "./errors";
 
 /**
  * Custom error class for Kintone API errors
@@ -63,7 +64,7 @@ export class KintoneClient {
       return new KintoneError(error.message);
     }
 
-    return new KintoneError("Unknown error occurred");
+    return new KintoneError(getErrorMessage("unknownError"));
   }
 
   private async withErrorHandling<T>(operation: () => Promise<T>): Promise<T> {
@@ -198,7 +199,9 @@ export class KintoneClient {
       return {
         success: false,
         error:
-          error instanceof KintoneError ? error.message : "Connection failed",
+          error instanceof KintoneError
+            ? error.message
+            : getErrorMessage("connectionFailed"),
       };
     }
   }