fix(lobby): land in the opened game on enqueue + keep open games active in the lobby

Review fixes for open-game auto-match: decodeMatchResult dropped the game when matched=false (an open game awaiting an opponent), so the client never navigated into it - decode the game whenever present. The lobby grouped open games (status != 'active') into 'finished'; treat 'open' as in progress in groupGames/isMyTurn and resultBadge. The under-board status bar now reads "Opponent's turn" while the empty opponent seat is to move (instead of the searching placeholder). The New Game rule toggle is shown from the start when a Russian variant is available, so selecting a variant no longer shifts the layout.

Regression tests: codec (game decoded with matched=false), lobbysort + result (open is in progress), and the new-game e2e updated. UI-only; no backend or schema change.

ui/src/lib/result.ts

@@ -12,7 +12,7 @@ export interface ResultBadge {
 export function resultBadge(game: GameView, myId: string): ResultBadge {
   const me = game.seats.find((s) => s.accountId === myId);
 
-  if (game.status === 'active') {
+  if (game.status === 'active' || game.status === 'open') {
     return game.toMove === me?.seat
       ? { key: 'result.yourMove', emoji: '🟢' }
       : { key: 'result.oppMove', emoji: '⏳' };