fix(ui): offline in-game — usable dictionary check + hide (not disable) resign/chat

Two fixes from contour testing of the offline-in-game UX:

- The dictionary word check was unusable offline (Check button disabled) when the
  panel was reached while already offline: CheckScreen fetched the variant + pinned
  version over the network in onMount, which fails offline, leaving the default
  variant so input sanitising stripped every letter. Seed both from the cached game
  (present once the board has opened) so the input and the on-device dawg fallback
  work without a round-trip; the network refresh still runs when online and on a
  cold deep-link.
- The resign and chat controls were only functionally disabled (chat) or not gated
  at all (resign) offline, so they still looked active. Hide both while offline,
  matching the frozen social controls.

Tests: the in-game offline e2e now asserts the drawer action icons are hidden (not
disabled); a new e2e guards the offline dictionary flow. Docs updated.

docs/ARCHITECTURE.md

@@ -124,8 +124,8 @@ dropped). Horizontal scaling is explicit future work.
   switch and no device-local create paths. The machine still tracks reachability there, though: a
   connection lost **inside an online game** is surfaced on **every platform**, driven off the machine's
   confirmed-offline state (`netState.offline`, not `offlineMode.active`) — the game screen shows a
-  *connection lost* banner and **freezes** the tray, the move controls, the add-friend/block controls and
-  the chat/dictionary entry (a started move stays a draft, re-committed by the player on reconnect), and
+  *connection lost* banner, **freezes** the tray and move controls, and hides the resign, add-friend/block
+  and chat/dictionary controls (a started move stays a draft, re-committed by the player on reconnect), and
   the word-check tool falls back to the game's pinned on-device dictionary (`ui/src/lib/dict/check.ts`,
   exact when that dawg is cached, else *unavailable*) with its network-only complaint and external
   look-up hidden.