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.

docs/FUNCTIONAL.md

@@ -68,7 +68,9 @@ account is kept and the guest's games move into it. A merge is blocked only whil
 two accounts share a game still in progress.
 
 ### Lobby & matchmaking
-Bottom tab menu: **my games**, **profile**. The **my games** list groups games into three
+The lobby lists **my games** and offers a bottom tab bar — new game, statistics, and a
+**⚙️ settings** tab opening the settings hub (settings, profile, friends, about). The
+**my games** list groups games into three
 sections — *your turn*, *opponent's turn* and *finished* (empty sections are hidden) — and
 orders them so the games awaiting your move come first, the longest-waiting on top, while
 opponent-turn and finished games are most-recent first; it renders as a compact,
@@ -128,18 +130,20 @@ digits, valid for twelve hours), or send a **request to someone you have played
 with** — they accept, ignore it (a request lapses after thirty days and can then be
 re-sent), or decline (a decline blocks further requests from you until they hand you
 a code). Cancelling your own pending request withdraws it; unfriending removes the
-friendship. In a game, an **add to friends** item for each opponent mirrors the live
-relationship: it reads *request sent* (disabled) while a request is pending or was
-declined, and *in friends* once accepted — updating in place the moment the opponent
-answers, and staying correct across reloads. Block globally — switch off incoming chat
+friendship. In a game, each opponent's score card carries an **add-to-friends 🤝** control (while the
+move history is open) that mirrors the live relationship: it confirms with a tap on a fading
+✅ (the card reads *Add friend?* while confirming), goes **disabled** while a request is
+pending or was declined, and **disappears** once you are friends — updating in place the
+moment the opponent answers, and staying correct across reloads. Block globally — switch off incoming chat
 and/or friend requests — and block individual players (a per-user block hides that
 person's chat and stops requests and game invitations both ways; it also ends any
 existing friendship). Per-game chat is for quick reactions: messages are short
 (up to 60 characters) and may not contain links, email addresses or phone numbers,
 even disguised. Nudge the player whose turn is awaited at most once per hour (the
 nudge is part of the game chat); the out-of-app push is delivered via the platform.
-Chat and the word-check tool open as their **own screens** (with a back to the game), and a
-new chat message raises an **unread badge** on the game's menu until the chat is opened.
+Chat and the word-check tool share one **comms screen** with **💬 chat** / **🔎 dictionary**
+tabs, reached from the 💬 in the move-history header (with a back to the game); a new chat
+message raises an **unread badge** on the game's score bar and the 💬 until the chat is opened.
 
 ### Profile & settings
 Edit the display name (letters joined by a single space / "." / "_" separator, with an