fix(ui): let a caller retry a failed auto-router model fetch in-form

A failed fetchAvailableModels call disabled every preset with no way to recover short of closing and reopening the modal, even for a transient error. Surface the failure next to the template selector with a Retry action that re-runs the same useQuery.

ui/litellm-dashboard/src/components/add_model/add_auto_router_tab.test.tsx

@@ -184,6 +184,22 @@ describe("AddAutoRouterTab", () => {
     expect(isOptionDisabled(optionByLabel("OpenAI Family")!)).toBe(true);
   });
 
+  // A failed fetch must not strand the caller: Retry re-runs the same query, and a caller who
+  // only hit a transient error can recover without closing and reopening the whole modal.
+  it("recovers presets once Retry re-fetches successfully", async () => {
+    const user = userEvent.setup();
+    mockFetchAvailableModels.mockRejectedValueOnce(new Error("boom")).mockResolvedValueOnce(ALL_FAMILY_MODELS);
+
+    renderWithProviders(<Harness />);
+    await waitFor(() => expect(screen.getByRole("button", { name: /retry/i })).toBeInTheDocument());
+
+    await user.click(screen.getByRole("button", { name: /retry/i }));
+
+    openTemplateDropdown();
+    await waitFor(() => expect(isOptionDisabled(optionByLabel("Anthropic Family")!)).toBe(false));
+    expect(mockFetchAvailableModels).toHaveBeenCalledTimes(2);
+  });
+
   // The headline behavior: selecting a preset must pre-fill the tier config so the created
   // router carries the preset's models. Real tier validation runs here (getMissingTiersError is
   // not stubbed), so if selection stopped pre-filling, the empty tiers would either block the

ui/litellm-dashboard/src/components/add_model/add_auto_router_tab.tsx

@@ -109,6 +109,7 @@ const AddAutoRouterTab: React.FC<AddAutoRouterTabProps> = ({
     data: modelInfo = [],
     isLoading: modelsLoading,
     isError: modelsError,
+    refetch: refetchModels,
   } = useQuery({
     queryKey: ["availableModels", "autoRouter", accessToken],
     queryFn: () => fetchAvailableModels(accessToken),
@@ -357,6 +358,14 @@ const AddAutoRouterTab: React.FC<AddAutoRouterTabProps> = ({
             {showValidationErrors && !selectedPreset && (
               <div className="text-xs mt-1 text-red-500">Please select a template</div>
             )}
+            {modelsError && (
+              <div className="text-xs mt-1 text-red-500">
+                Could not load available models.{" "}
+                <button type="button" className="underline" onClick={() => refetchModels()}>
+                  Retry
+                </button>
+              </div>
+            )}
           </div>
 
           <Form.Item