UI: taller tg-fullscreen header + labelled hub tabs

- tg-fullscreen: +20px header height — without the (removed) hamburger the
  title bar lost its bulk and sat flush on Telegram's native nav band.
- Settings/Comms hub tabs gain text labels under the icons (Settings /
  Profile / Friends / Info and Chat / Dictionary); the icon is aria-hidden
  so the label names the button. New i18n keys about.tab, game.dictionary.

docs/UI_DESIGN.md

@@ -35,8 +35,9 @@ Login uses `Screen`.
   routes `/settings|/profile|/friends|/about` and `/game/:id/{chat,check}` survive as hub
   entry points (so a Telegram friend-code deep-link still lands on the Friends tab).
 - **Tab bar** (`TabBar.svelte`): square, borderless, evenly distributed buttons — a large
-  emoji icon over a tiny truncated label (hub tabs are **icon-only**). A press highlights a
-  rounded **square** behind the icon; a hub's **selected** tab stays highlighted (a filled
+  emoji icon over a tiny truncated label (the icon is `aria-hidden`, so the label names the
+  button). A press highlights a rounded **square** behind the icon; a hub's **selected** tab
+  stays highlighted (a filled
   square with an accent underline). A red count **badge** rides the icon's corner — on the
   lobby ⚙️ tab and the hub's 🤝 Friends tab for pending incoming friend requests (invitations
   keep their own lobby section), and on the Hint tab for the remaining count. No text