fix(desktop): show non-blocking notification on fallback runtime probe

When shouldPreserveConfiguredOnFallback keeps configured=true, also call
notifyError('runtime-not-ready', ...) so the user knows the backend wasn't
verified instead of silently proceeding. Adapted from @mohamedorigami-jpg's
approach in PR #37634.

apps/desktop/src/store/onboarding.test.ts

@@ -154,6 +154,31 @@ describe('refreshOnboarding', () => {
     expect(window.localStorage.getItem('hermes-desktop-onboarded-v1')).toBeNull()
   })
 
+  it('shows a non-blocking notification when preserving configured on fallback', async () => {
+    const notifyErrorSpy = vi.spyOn(
+      await import('@/store/notifications'),
+      'notifyError'
+    )
+
+    installApiMock(vi.fn())
+    $desktopOnboarding.set(
+      baseState({
+        configured: true,
+        providers: [provider('cached')],
+        reason: null,
+        requested: false
+      })
+    )
+
+    await refreshOnboarding(onboardingContext(fallbackTimeoutGateway()))
+
+    expect(notifyErrorSpy).toHaveBeenCalledWith(
+      'runtime-not-ready',
+      expect.stringContaining('could not verify the running backend')
+    )
+    expect($desktopOnboarding.get().configured).toBe(true)
+  })
+
   it('still surfaces onboarding when fallback failure happens before configured state', async () => {
     const api = vi.fn(async ({ path }: { path: string }) => {
       if (path === '/api/providers/oauth') {

apps/desktop/src/store/onboarding.ts

@@ -526,6 +526,14 @@ export async function refreshOnboarding(ctx: OnboardingContext) {
 
   const state = $desktopOnboarding.get()
   if (shouldPreserveConfiguredOnFallback(runtime, state)) {
+    // Gateway probes timed out but the user was already configured — don't
+    // downgrade to the blocking onboarding overlay. Surface a non-blocking
+    // notification so the user knows the backend wasn't verified.
+    notifyError(
+      'runtime-not-ready',
+      'Hermes Desktop could not verify the running backend on startup. Some features may be unavailable until the gateway is reachable.'
+    )
+
     return false
   }