UI: tab-bar navigation — drop the hamburger

Replace Menu.svelte (hamburger) everywhere with tab-bar navigation:
- Settings hub (SettingsHub) from the lobby ⚙️ tab: Settings/Profile/
  Friends/About as in-place tabs, back → lobby; the lobby ⚙️ badge counts
  incoming friend requests (invitations keep their own lobby section).
- Comms hub (CommsHub) from the move-history 💬: Chat/Dictionary tabs,
  back → game; Dictionary only while the game is active.
- Game menu items relocate into the open history: 🏁 leave / 📤 export in
  the header, 🤝 add-friend per opponent card, 💬 comms; unread chat is
  badged on the score bar + the 💬.
- TapConfirm (tap → fading ✅ → tap) replaces the Skip/Hint press-and-hold
  popovers and drives the add-friend confirm.
- Fix the move-history "jump": the slid board is inert and the stage can't
  scroll, so a swipe up genuinely closes the history.

Remove Menu.svelte + HoldConfirm.svelte. Docs: UI_DESIGN, FUNCTIONAL(+ru),
PRERELEASE. UI check/unit/build/bundle/e2e (Chromium+WebKit) all green.

PRERELEASE.md

@@ -24,6 +24,7 @@ the edge before prod. Each phase maps back to the owner's raw pre-release TODO l
 | R5 | Bundle slimming | 6 | **done** |
 | R6 | Refactor + docs reconciliation + de-staging | 7 | **done** |
 | R7 | Final stress run + tuning | 9b | **done** |
+| UI | Tab-bar navigation redesign (drop the hamburger) | owner ad-hoc | **done** |
 | → | Stage 18 — prod contour deploy | — | see [`PLAN.md`](PLAN.md) |
 
 ## Key findings (these reshaped the raw list — read before starting a phase)
@@ -413,3 +414,21 @@ Then Stage 18.
     more cores per node (recorded in the prod-sizing recommendation).
   - **No schema change → no contour DB wipe.** Bake-back: `loadtest/REPORT-R7.md` (new), `loadtest/README.md`,
     `docs/TESTING.md`, the telemetry/observability section of `docs/ARCHITECTURE.md`, the repo-layout line in `CLAUDE.md`.
+
+- **UI — Tab-bar navigation redesign** (owner ad-hoc, not on the raw TODO list): drop the hamburger
+  `Menu.svelte` everywhere (it fought the Telegram-fullscreen layout, where it had to be re-centred).
+  - **Locked decisions (interview):** the in-Settings sub-nav is a **bottom TabBar with the active tab
+    highlighted** (icon-only); **Export GCG** moves to the left slot of the move-history header (free in a
+    finished game, where 🏁 *leave* does not apply); the lobby **⚙️ badge counts incoming friend requests
+    only** (invitations keep their own lobby section); unread chat is badged on **the score bar and the 💬**.
+  - **What shipped:** a ⚙️ **Settings hub** (`screens/SettingsHub.svelte`) over the existing
+    Settings/Profile/Friends/About bodies and an in-game **comms hub** (`game/CommsHub.svelte`) over
+    chat + dictionary, both with in-place tabs and a fixed back target; the game's menu items relocate into
+    the open move history (🏁 leave / 📤 export + 💬 comms header) and the player cards (🤝 add-friend); a
+    shared **TapConfirm** (`components/TapConfirm.svelte`, `lib/tapconfirm.ts`) — tap → fading ✅ → tap —
+    replaces the Skip/Hint press-and-hold popovers and drives the add-friend confirm. Fixed the move-history
+    "jump" bug (the slid board is now inert and the stage can't scroll, so a swipe up genuinely closes it).
+    `Menu.svelte` + `HoldConfirm.svelte` removed.
+  - **No schema/wire change → no contour DB wipe.** Bake-back: `docs/UI_DESIGN.md`, `docs/FUNCTIONAL.md`
+    (+`_ru`). Regression gate: UI `check` + unit (`tapconfirm`) + build + bundle budget + e2e (Chromium &
+    WebKit), all green.