fix(offline): hotseat review fixes + PWA stale-shell (SW route order)

Owner review of the pass-and-play PR:
- Roster delete (bug): a correct host PIN now ARMS a delete cross next to
  the row (mirroring the lobby delete) instead of removing it silently;
  tapping the kebab again clears the host authorisation.
- Variant picker (UX): replace the dropdown with the Quick-Match variant
  plaques + the multiple-words toggle, one-to-one.
- Keyboard layout (UX): the roster sits in a scroll region with the Start
  button pinned (friends-form pattern), so a name input's soft keyboard
  shrinks the region instead of leaving a full-height blank spacer painted
  behind the keyboard.
- e2e: variant via plaque + a row-delete (arm then cross) regression step.

PWA stale-version (pre-existing, same PR):
- sw.ts: register the network-first NavigationRoute BEFORE precacheAndRoute.
  Workbox matches in registration order and the precache route (directoryIndex
  index.html) shadowed the shell navigation, serving it cache-first — the old
  build's __APP_VERSION__ until a second load. Fixes both the maintenance
  self-reload and a cold open after a deploy. Doc updated (ARCHITECTURE).

ui/e2e/hotseat.spec.ts

@@ -54,14 +54,26 @@ test.describe('offline hotseat (pass-and-play)', () => {
     await typePin(page, '9999');
     await page.getByRole('button', { name: /^(No|Нет)$/ }).click();
 
-    // Pick the English variant if the picker offers a choice.
-    const variant = page.locator('.fg select').first();
-    if (await variant.isEnabled()) await variant.selectOption('scrabble_en');
+    // Pick the English variant (the plaques mirror Quick Match; "Scrabble" is the Latin English name).
+    await page.locator('.variant', { hasText: 'Scrabble' }).click();
 
     // Two players: Ann (PIN-locked) and Bob (open).
     await page.locator('.pname').nth(0).fill('Ann');
     await page.locator('.pname').nth(1).fill('Bob');
-    await page.locator('.prow').nth(0).locator('.plink').click(); // Ann's seat PIN
+
+    // Row-delete: a 3rd player's kebab asks the host PIN, which ARMS a ❌ (not a silent delete);
+    // tapping the ❌ removes the row.
+    await page.getByRole('button', { name: /Add player|Добавить/i }).click();
+    await expect(page.locator('.prow')).toHaveCount(3);
+    await page.locator('.prow').nth(2).locator('.pkebab').click();
+    await typePin(page, '9999');
+    const rowDel = page.locator('.prow').nth(2).locator('.prow-del');
+    await expect(rowDel).toBeVisible();
+    await rowDel.click();
+    await expect(page.locator('.prow')).toHaveCount(2);
+
+    // Lock Ann's seat with a PIN.
+    await page.locator('.prow').nth(0).locator('.plink').click();
     await typePin(page, '1234');
     await typePin(page, '1234');