fix: add form validation error feedback in agent edit dialog

- Add onFormError callback to show toast when validation fails
- This helps debug why the save button appears to do nothing

web/app/dashboard/agents/_components/edit.tsx

@@ -266,6 +266,16 @@ function AgentEditDialogBody({
     await onSubmit(buildPayload(values));
   }
 
+  function onFormError(errors: object) {
+    console.error("Agent form validation errors:", errors)
+    const firstError = Object.values(errors).find(
+      (e: unknown) => (e as { message?: string })?.message
+    ) as { message?: string } | undefined
+    if (firstError?.message) {
+      toast.error(firstError.message)
+    }
+  }
+
   return (
     <ProjectDialog
       open={open}
@@ -284,7 +294,7 @@ function AgentEditDialogBody({
           </Button>
           <Button
             type="button"
-            onClick={() => handleSubmit(onFormSubmit)()}
+            onClick={() => handleSubmit(onFormSubmit, onFormError)()}
             disabled={saving || loading}
           >
             {saving ? "保存中..." : "保存"}