feat(10-02): integrate RemoteNamePreview into BackendSelectionStep with tests

- Add RemoteNamePreview integration tests: empty-state [my-remote] on render
- Add live-update test: typing 'test-remote' shows [test-remote] in DOM
- Fix getByText(/required/i) ambiguity: use alert.textContent.toMatch instead
  (description paragraph now contains 'required' — Rule 1 bug fix)
- BackendSelectionStep.tsx changes already committed (watch, helpText, RemoteNamePreview)

src/components/wizard/BackendSelectionStep.test.tsx

@@ -60,6 +60,22 @@ describe('BackendSelectionStep', () => {
     });
   });
 
+  describe('RemoteNamePreview integration', () => {
+    it('shows empty-state placeholder [my-remote] on initial render', () => {
+      renderStep();
+      expect(screen.getByText('[my-remote]')).toBeDefined();
+    });
+
+    it('updates preview to [test-remote] as user types', async () => {
+      const user = userEvent.setup();
+      renderStep();
+      const nameInput = screen.getByRole('textbox');
+      await user.clear(nameInput);
+      await user.type(nameInput, 'test-remote');
+      expect(screen.getByText('[test-remote]')).toBeDefined();
+    });
+  });
+
   describe('WIZD-04: remote name field', () => {
     it('renders remote name input at the top of the step', () => {
       renderStep();
@@ -87,8 +103,9 @@ describe('BackendSelectionStep', () => {
       await user.click(azureButton);
       // Error should appear after async validation
       await waitFor(() => {
-        expect(screen.getByRole('alert')).toBeDefined();
-        expect(screen.getByText(/required/i)).toBeDefined();
+        const alert = screen.getByRole('alert');
+        expect(alert).toBeDefined();
+        expect(alert.textContent).toMatch(/required/i);
       });
     });