feat(e2e): #146 MTProto Telegram user client runner

- Add standalone C# console runner tests/e2e/runner/ using WTelegramClient
- Provide TelegramUserClient wrapper: login, create supergroup, invite bot,
  send messages/commands, read recent messages, wait for bot reply
- Add .env.example and runner .gitignore to keep secrets/session files out of git
- Update E2E README with runner instructions and status table
- Runner project intentionally excluded from GM-Relay.slnx to avoid CI/AOT impact

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/e2e/runner/.gitignore

@@ -0,0 +1,5 @@
+.env
+*.session
+bin/
+obj/
+packages.lock.json