feat(lobby): drop left honest-AI games from the finished list

A finished honest-AI (vs_ai) game the player left — by resigning or by
abandoning it to the 7-day inactivity timeout (end_reason 'resign'/'timeout')
— no longer appears in that player's own lobby finished list.

The new game.Service.ListForLobby filters ListForAccount for the lobby
endpoint only; the admin console and the account-merge count keep the full
set. The filter keys on the game's end reason, not on which seat left, so it
extends to any player should the robot ever resign.

docs/FUNCTIONAL.md

@@ -80,7 +80,10 @@ finishes**, its status icon **blinks twice** to draw the eye (an opponent's-turn
 silent, applied in place). You can **remove a finished game from your own list**:
 swipe a finished row left (or, on desktop, tap its **⋮**) to reveal a **❌**, then tap it.
 The removal is per-account and permanent — the game disappears only from your list and stays
-in the other players' lists, and there is no undo. The game types offered on **New Game** are
+in the other players' lists, and there is no undo. A finished **AI game (🤖) you left** — by
+resigning or by letting it lapse to the 7-day timeout — drops from your *finished* list
+automatically, with no swipe needed; a normally finished AI game stays until you remove it, and
+no other game type is auto-removed. The game types offered on **New Game** are
 limited to the languages the player's sign-in service supports (English → Scrabble;
 Russian → Scrabble + Erudite; a bilingual service shows all three, and the web client is
 unrestricted). Variants are shown by their **display name** — both Scrabble variants read