Stage 17 round 5 docs: bake the bug fixes + UI polish + L2 into live docs

- ARCHITECTURE: resign on the opponent's turn (ResignSeat + turn-check bypass); robots
  block chat but accept-and-ignore friend requests; quick-match /lobby/cancel; the admin
  robot play-to-win intent + next-move ETA panel.
- UI_DESIGN: even A->B zoom (recentre only on zoom-in), pinch, drop-target highlight,
  shuffle ≤0.3s + reduce-motion, borderless make-move disabled on illegal, variant title.
- FUNCTIONAL (+ru): variant display names (Scrabble/Erudite); robot ignores friend requests.
- PLAN: round-5 refinements bullet (+ the bilingual two-Scrabble open edge).

docs/ARCHITECTURE.md

@@ -235,7 +235,10 @@ Key points:
   applying the end-game rack-value adjustment, or a resignation. On a
   **resignation the resigner keeps their accumulated score (no rack adjustment)
   and never wins**: the win goes to the highest score among the remaining seats,
-  unconditionally the other player in a two-player game. The engine exposes a
+  unconditionally the other player in a two-player game. A player may resign **on the
+  opponent's turn** (a forfeit is not a turn-scoped move): `engine.ResignSeat(seat)`
+  resigns that player's own seat whoever is to move, and the game domain skips the turn
+  check for resign (Stage 17). The engine exposes a
   decoded, solver-free API (`SubmitPlay`/`SubmitExchange`/`EvaluatePlay`/
   `HintView`/`Hand`) so `internal/game` drives it without importing the solver.
 - The **game domain** (`internal/game`) owns everything the engine does not —
@@ -301,9 +304,10 @@ from the game's bag `seed` (a restart-stable FNV-1a mix), so a background driver
 (`robot.Service.Run`, mirroring the turn-timeout sweeper) recomputes the same
 behaviour on every scan and after a restart — the same philosophy as journal
 replay. A pool of durable accounts — each a `kind='robot'` identity (§4), keyed
-`robot-<lang>-<index>` and provisioned at startup with chat and friend requests
-blocked — backs the human-like names; those two profile toggles are all the
-friend/DM blocking requires (there is no DM surface; chat is per-game). Names are
+`robot-<lang>-<index>` and provisioned at startup with **chat blocked but friend
+requests open** — a request to a robot is accepted as pending and expires unanswered
+(the robot never responds), mirroring a human who ignores it (Stage 17); the chat
+block backs the human-like names (there is no DM surface; chat is per-game). Names are
 **composed per language** from a first-name pool (32 full + 32 colloquial forms) and
 a surname pool (gender-agreed for Russian) in one of three forms (first only /
 first + surname initial / first + full surname), deterministically per pool slot so
@@ -331,6 +335,8 @@ English game the Latin pool.
 - **Observability**: robot accounts accrue ordinary statistics (§9) — the
   authoritative balance metric (target ≈ 40% robot wins) — and a
   `robot_games_finished_total` OTel counter plus a per-finish log give a live view.
+  The **admin game card** surfaces each robot seat's per-game play-to-win intent (from
+  the seed) and, on the robot's turn, its deterministic **next-move ETA** (Stage 17).
 
 ## 8. Lobby & social
 
@@ -342,6 +348,9 @@ English game the Latin pool.
   robot (§7) and starts the game. On a pairing or substitution the matchmaker
   emits a **match-found** notification (§10), delivered over the live stream;
   `Poll` remains as a fallback for a client that is not currently streaming.
+  **Cancel** (`POST /lobby/cancel`) removes the player from the pool and drops any
+  pending matched result, so a cancelled quick-match is dequeued rather than left for
+  the reaper to robot-substitute (Stage 17).
 - **Friends** (Stage 8): two add paths over one `friendships` table. A **one-time
   code** the to-be-added player issues (a `friend_codes` row: 6-digit numeric,
   SHA-256-hashed, **12 h** TTL, one live code per issuer, single-use, redeem