feat(ui): explicit offline state inside an online game (+ offline word check)

When an online game loses the connection the game screen now says so and freezes
instead of silently greying out: a "connection lost" banner appears and the rack,
the move controls, the add-friend/block controls and the chat/dictionary entry all
disable (a started move stays a draft, committed by the player on reconnect). It is
driven off the net-state machine (netState.offline), so it also covers the
Telegram/VK mini-apps, where a lost connection was previously mute in-game.

If the player is already in the dictionary when the drop happens, the word check
falls back to the game's pinned on-device dictionary (exact when that dawg is
cached; "unavailable offline" otherwise) and the network-only complaint + external
look-up hide. Chat, when already open, keeps its existing read-only degrade
(send/nudge disable). New pure helper localWordCheck is unit-tested; the in-game
gating gets an e2e.

docs/FUNCTIONAL.md

@@ -229,7 +229,10 @@ brief warm-up shows on the first open otherwise — and falls back to the server
 local dictionary is unavailable. The dictionary check tool is
 unlimited and offers a complaint on any result; for a word it finds, it also links out to an
 external reference dictionary (gramota.ru for Russian games, scrabblewordfinder.org for
-English) to look it up. Hints are governed per game —
+English) to look it up. While offline in an online game the check runs against the game's own
+dictionary on the device — the same verdict as the server when that dictionary is available,
+otherwise it reads *unavailable offline* — and the complaint and the external look-up, which both
+need the network, are hidden. Hints are governed per game —
 whether they are allowed and how many each player starts with — and draw on a
 personal hint wallet once the per-game allowance is spent. Against the robot
 (**vs_ai**) hints are instead **unlimited and wallet-free**, but idle-gated as an
@@ -322,6 +325,16 @@ offline on its own, and restoring the network returns it online by itself. There
 switch to remember: a brief drop is ridden out quietly and only a sustained loss turns the chrome
 offline, so you are never interrupted for a hiccup.
 
+**Losing the connection while inside an online game** is surfaced on **every platform, including the
+Telegram/VK mini-apps** — unlike the offline-play mode above, which is web/native only — because an
+online game needs the server for every move. A slim *connection lost* banner appears at the top of the
+board and the play area **freezes**: the rack, the move controls, the add-friend/block controls and the
+chat/dictionary entry all disable, while a move you had started stays on the board as a draft. Nothing
+is sent; when the connection returns the banner clears, the controls come back and you commit the move
+yourself. If you were already in the chat or the dictionary when the drop happened you stay there — chat
+becomes read-only (send and nudge disable) and the dictionary keeps checking words against the game's
+on-device dictionary.
+
 ### Staying up to date
 When a new client version is required, the app does not lock you out. On the **native** app a
 too-old build shows a notice with **Update** (opens the store) and **Play offline** (dismiss and keep