fix(frontend): route agent checks to gateway (#1572)

* fix(frontend): route agent checks to gateway

* fix(frontend): proxy langgraph requests locally

* fix(frontend): keep zh-CN text readable

* fix(frontend): add exact local api rewrites

* fix(frontend): support docker-safe internal rewrites

* Update frontend/src/core/agents/api.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

frontend/src/core/i18n/locales/en-US.ts

@@ -194,7 +194,8 @@ export const enUS: Translations = {
     nameStepInvalidError:
       "Invalid name — use only letters, digits, and hyphens",
     nameStepAlreadyExistsError: "An agent with this name already exists",
-    nameStepCheckError: "Could not verify name availability — please try again",
+    nameStepCheckError:
+      "Could not reach the DeerFlow backend to verify name availability. Start the backend or set NEXT_PUBLIC_BACKEND_BASE_URL, then try again.",
     nameStepBootstrapMessage:
       "The new custom agent name is {name}. Let's bootstrap it's **SOUL**.",
     agentCreated: "Agent created!",