docs(telegram): invert chat-gate strategy in docs; tune logs; i18n text

- Bake the final default-allow + mute-the-ineligible strategy into
  docs/ARCHITECTURE.md, docs/FUNCTIONAL.md (+_ru), platform/telegram/README.md,
  the deploy compose comment and the PRERELEASE tracker. The live test proved a
  per-user grant cannot exceed a deny-by-default group (Telegram intersects the
  chat default with the per-user permission), so the chat allows sending by
  default and the bot restricts the ineligible instead of granting the eligible.
- Lower the per-event chat_member trace and eligibility evaluation to Debug;
  keep the actual mute/unmute actions, the startup self-check and warnings at
  Info, so prod logs only what the bot did.
- Update game.searchingForOpponent (Searching -> Waiting for opponent / Поиск ->
  Ждём соперника) and the quickmatch e2e assertions to match.

ui/src/lib/i18n/en.ts

@@ -63,7 +63,7 @@ export const en = {
   'game.yourTurn': 'Your turn',
   'game.yourTurnBy': '{name}: Your turn!',
   'game.opponentsTurn': "Opponent's turn",
-  'game.searchingForOpponent': 'Searching for opponent…',
+  'game.searchingForOpponent': 'Waiting for opponent…',
   'game.waiting': "Waiting for {name}",
   'game.makeMove': 'Make move',
   'game.reset': 'Reset',

ui/src/lib/i18n/ru.ts

@@ -64,7 +64,7 @@ export const ru: Record<MessageKey, string> = {
   'game.yourTurn': 'Ваш ход',
   'game.yourTurnBy': '{name}: Ваш ход!',
   'game.opponentsTurn': 'Ход соперника',
-  'game.searchingForOpponent': 'Поиск соперника...',
+  'game.searchingForOpponent': 'Ждём соперника…',
   'game.waiting': 'Ожидаем {name}',
   'game.makeMove': 'Сделать ход',
   'game.reset': 'Сброс',