test(#411): QA-015 — add credentials fallback test + fix refreshSession test name

Add test for non-string error.message fallback in handleCredentialsLogin.
Rename misleading refreshSession test to match actual behavior.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/app/(auth)/login/page.test.tsx

@@ -341,6 +341,33 @@ describe("LoginPage", (): void => {
     expect(mockPush).not.toHaveBeenCalled();
   });
 
+  it("should show fallback PDA-friendly message when error.message is not a string", async (): Promise<void> => {
+    mockFetchConfig(EMAIL_ONLY_CONFIG);
+    // Return an error object where message is NOT a string (e.g. numeric code, no message field)
+    mockSignInEmail.mockResolvedValueOnce({
+      error: { code: 123 },
+    });
+    const user = userEvent.setup();
+
+    render(<LoginPage />);
+
+    await waitFor((): void => {
+      expect(screen.getByLabelText(/email/i)).toBeInTheDocument();
+    });
+
+    await user.type(screen.getByLabelText(/email/i), "test@example.com");
+    await user.type(screen.getByLabelText(/password/i), "wrong");
+    await user.click(screen.getByRole("button", { name: /continue/i }));
+
+    await waitFor((): void => {
+      expect(
+        screen.getByText("Unable to sign in. Please check your credentials and try again.")
+      ).toBeInTheDocument();
+    });
+
+    expect(mockPush).not.toHaveBeenCalled();
+  });
+
   it("shows parseAuthError message on unexpected sign-in exception", async (): Promise<void> => {
     mockFetchConfig(EMAIL_ONLY_CONFIG);
     mockSignInEmail.mockRejectedValueOnce(new TypeError("Failed to fetch"));