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.

deploy/docker-compose.yml

@@ -269,8 +269,9 @@ services:
       TELEGRAM_BOT_TOKEN: ${TELEGRAM_BOT_TOKEN:-}
       TELEGRAM_GAME_CHANNEL_ID: ${TELEGRAM_GAME_CHANNEL_ID:-}
       # The moderated discussion chat (a channel's linked group) the bot gates write
-      # access in. Empty disables gating; the bot must be an admin there with the
-      # "Ban users" right and receives chat_member updates only as an admin.
+      # access in. Empty disables gating. The group must ALLOW sending by default — the bot
+      # only restricts (mutes the ineligible) — and the bot must be an admin there with the
+      # "Ban users" right; chat_member updates are delivered only to a chat admin.
       TELEGRAM_CHAT_ID: ${TELEGRAM_CHAT_ID:-}
       # The optional standalone promo bot (its own token) answering /start with a button
       # into the main bot's app. Empty disables it; when set it needs the main bot's