Stage 17 (contour round 4a): quick fixes

- #4 bag label: '{n} in the bag' / 'Bag is empty' (was 'Bag {n}')
- #6 allow a single trailing dot in display names (backend + UI regex + tests)
- #1 double-tap zooms toward the tapped cell, not the top-left
- #8 shuffle fires a short multi-pulse haptic
- #11 highlighted/flashing tiles darken their bottom edge too (shadow joins the flash)
- #13 toast slides up from the bottom and fades out
- #7 hide the logout button (kept wired behind `hidden`)
- #16 admin game seats: left-align numeric columns, clarify the 'Hints used' header

ui/src/lib/i18n/en.ts

@@ -46,7 +46,8 @@ export const en = {
   'new.find': 'Find a game',
   'new.searching': 'Looking for an opponent…',
 
-  'game.bag': 'Bag {n}',
+  'game.bag': '{n} in the bag',
+  'game.bagEmpty': 'Bag is empty',
   'game.hints': 'Hints {n}',
   'game.yourTurn': 'Your turn',
   'game.waiting': "Waiting for {name}",