fix(feedback): theme buttons, badge the Info button, simplify admin actions

- style the About feedback button and the form's Send/attach/remove buttons with
  the accent/border tokens used by the New Game CTA, so they follow light/dark
  theme (the previous .btn/.ghost classes were not defined globally); the attach
  button is a neutral 📎 icon button with an aria-label
- show a round badge on the About 'Feedback' button when a reply is waiting
- admin: one 'ban from feedback' checkbox shared by Delete and Delete-all (via
  button formaction); hide Mark read when already read and Archive when archived
- e2e: match the About button by substring (its name gains the badge)

ui/e2e/feedback.spec.ts

@@ -14,7 +14,9 @@ async function openFeedback(page: Page): Promise<void> {
   await page.getByRole('button', { name: /Settings/ }).click();
   await expect(page.locator('.pane')).toHaveCount(1);
   await page.getByRole('button', { name: 'Info', exact: true }).click();
-  await page.getByRole('button', { name: 'Feedback', exact: true }).click();
+  // The About "Feedback" button: its accessible name gains the "1" badge once a reply
+  // is waiting, so match by substring rather than exact.
+  await page.getByRole('button', { name: /Feedback/ }).click();
 }
 
 test('feedback: submit a message, then resend is blocked', async ({ page }) => {