Stage 17 round 6 (#11/#12): quick-game variant plaques with rules, flag, and move-limit

Each auto-match variant is now a lobby-style plaque: the display name with a flag on the
right (🇺🇸 / 🇷🇺; Erudit uses a bundled minimalist USSR flag SVG) and a one-line rules
summary below — bag size, the ё rule, and bonus differences, sourced from the engine
rulesets (Scrabble 100 · Скрэббл 104, ё a letter · Эрудит 131, ё=е, no centre ×2, +15).
The move-time limit (24h auto-match clock) is shown under the buttons. e2e locks it.

(Multiple-words-per-move is the same for every variant, so it is described in About/landing
rather than repeated on each button.)

ui/e2e/game.spec.ts

@@ -29,6 +29,14 @@ test('placing a tile and confirming via ✅ commits the move', async ({ page })
   await expect(page.locator('.make')).toBeHidden();
 });
 
+test('new game: variant buttons show a rules summary and the move-limit', async ({ page }) => {
+  await page.goto('/');
+  await page.getByRole('button', { name: /guest/i }).click();
+  await page.getByRole('button', { name: /New/ }).click(); // lobby tab bar -> auto-match
+  await expect(page.locator('.vrules').first()).toBeVisible(); // per-variant rules summary
+  await expect(page.locator('.movelimit')).toBeVisible(); // turn-time under the buttons
+});
+
 test('a pending tile recalls on double-tap, not on a single tap', async ({ page }) => {
   await openGame(page);
   await page.locator('.rack .tile').first().click();