fix(frontend): post-QA sprint 2 — i18n + alignment + textarea + action bar layout

- Translate all remaining French strings to English (toasts, buttons, banner)
- Fix UsersAdminPage create-form grid alignment: items-start + self-end on button wrapper
- Change execution_result from TextInput to TextArea (5 rows, multiline)
- Replace split Save RT / Save SOC footers + workflow div with a single sticky
  action bar (Save Red Team | Save SOC | Mark for review | Close | Delete)
- Update Vitest assertions to use English button labels

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

frontend/tests/SimulationFormPage.test.tsx

@@ -95,54 +95,54 @@ describe('SimulationFormPage — redteam mode (edit existing)', () => {
     expect(screen.getByLabelText(/Executed at/i)).not.toBeDisabled();
   });
 
-  it('shows "Marquer en revue" button when status is pending', async () => {
+  it('shows "Mark for review" button when status is pending', async () => {
     renderWithProviders(<EditPage />, {
       routerProps: { initialEntries: ['/engagements/42/simulations/7/edit'] },
     });
 
     await waitFor(() => {
-      expect(screen.getByRole('button', { name: /Marquer en revue/i })).toBeInTheDocument();
+      expect(screen.getByRole('button', { name: /Mark for review/i })).toBeInTheDocument();
     });
   });
 
-  it('does not show "Clôturer" when status is pending', async () => {
+  it('does not show "Close" when status is pending', async () => {
     renderWithProviders(<EditPage />, {
       routerProps: { initialEntries: ['/engagements/42/simulations/7/edit'] },
     });
 
-    await waitFor(() => screen.getByRole('button', { name: /Marquer en revue/i }));
-    expect(screen.queryByRole('button', { name: /Clôturer/i })).toBeNull();
+    await waitFor(() => screen.getByRole('button', { name: /Mark for review/i }));
+    expect(screen.queryByRole('button', { name: /^Close$/i })).toBeNull();
   });
 
-  it('shows "Marquer en revue" for in_progress status', async () => {
+  it('shows "Mark for review" for in_progress status', async () => {
     mock.onGet('/simulations/7').reply(200, { ...BASE_SIM, status: 'in_progress' });
     renderWithProviders(<EditPage />, {
       routerProps: { initialEntries: ['/engagements/42/simulations/7/edit'] },
     });
 
     await waitFor(() => {
-      expect(screen.getByRole('button', { name: /Marquer en revue/i })).toBeInTheDocument();
+      expect(screen.getByRole('button', { name: /Mark for review/i })).toBeInTheDocument();
     });
   });
 
-  it('shows "Clôturer" button when status is review_required', async () => {
+  it('shows "Close" button when status is review_required', async () => {
     mock.onGet('/simulations/7').reply(200, { ...BASE_SIM, status: 'review_required' });
     renderWithProviders(<EditPage />, {
       routerProps: { initialEntries: ['/engagements/42/simulations/7/edit'] },
     });
 
     await waitFor(() => {
-      expect(screen.getByRole('button', { name: /Clôturer/i })).toBeInTheDocument();
+      expect(screen.getByRole('button', { name: /^Close$/i })).toBeInTheDocument();
     });
   });
 
-  it('shows "Supprimer" button for redteam', async () => {
+  it('shows "Delete" button for redteam', async () => {
     renderWithProviders(<EditPage />, {
       routerProps: { initialEntries: ['/engagements/42/simulations/7/edit'] },
     });
 
     await waitFor(() => {
-      expect(screen.getByRole('button', { name: /Supprimer/i })).toBeInTheDocument();
+      expect(screen.getByRole('button', { name: /^Delete$/i })).toBeInTheDocument();
     });
   });
 });
@@ -242,13 +242,13 @@ describe('SimulationFormPage — SOC role + review_required (can edit SOC fields
     expect(screen.queryByTestId('soc-blocked-banner')).toBeNull();
   });
 
-  it('shows "Clôturer" for SOC when review_required', async () => {
+  it('shows "Close" for SOC when review_required', async () => {
     renderWithProviders(<EditPage />, {
       routerProps: { initialEntries: ['/engagements/42/simulations/7/edit'] },
     });
 
     await waitFor(() => {
-      expect(screen.getByRole('button', { name: /Clôturer/i })).toBeInTheDocument();
+      expect(screen.getByRole('button', { name: /^Close$/i })).toBeInTheDocument();
     });
   });
 });