fix(telegram): require entity mentions for group gating

[MonkeyLeeT]

Summary

Fix Telegram group mention gating so only real Telegram mention entities wake the bot.

Root Cause

TelegramAdapter._message_mentions_bot() returned True on any raw @<bot_username> substring before checking Telegram entities. That let unrelated text like foo@hermes_bot.example and longer handles like @hermes_botx bypass require_mention=true.

Changes

• remove the raw substring fast-path from gateway/platforms/telegram.py
• keep the existing entity-based mention and text_mention handling intact
• add regression tests for email-domain and longer-handle false positives in tests/gateway/test_telegram_group_gating.py

Validation

• scripts/run_tests.sh tests/gateway/test_telegram_group_gating.py -q

Closes #12545.

[teknium1]

Thanks for the contribution @MonkeyLeeT — closing as redundant. Commit e330112 on main refactored _message_mentions_bot() to use entity-only detection (MENTION and TEXT_MENTION entities), dropping the raw substring fallback that caused the foo@hermes_bot.example false positive you fixed here. Same fix, landed independently ~5 hours after your PR opened. Appreciate you catching this.