Fix Telegram group mentions failing to wake the bot when emoji precede @BotName, including media captions. Telegram entity offsets use UTF-16 code units, not Python string indices.

Modifications

• Parse mentions with the SDK and remove bot mentions using original UTF-16 offsets before rewriting text.

• Add regression coverage for emoji prefixes, multiple mentions, commands, and media captions.

• This is NOT a breaking change. / 这不是一个破坏性变更。

Screenshots or Test Results

Verification: send 😀 @BotName hello and multiple-emoji prefixes in a Telegram group; the bot now replies (screenshots below). Automated tests also cover media captions.

• python -m pytest tests/test_telegram_adapter.py -q: 38 passed.
• ruff format . and ruff check .: passed.

Before

After

Checklist

• 😊 If there are new features added in the PR, I have discussed it with the authors through issues/emails, etc.
  / 如果 PR 中有新加入的功能，已经通过 Issue / 邮件等方式和作者讨论过。

• 👀 My changes have been well-tested, and "Verification Steps" and "Screenshots" have been provided above.
  / 我的更改经过了良好的测试，并已在上方提供了“验证步骤”和“运行截图”。

• 📚 I checked the affected WebUI instructions and screenshots in docs/zh and docs/en against the changed navigation, page structure, and labels, and updated them in this PR (or explained why no documentation update is needed). For renamed, moved, or merged entry points, I included an old entry → new entry mapping in the documentation and changelog.
  / 我已对照变化后的 WebUI 入口、页面结构和术语，核对并在本 PR 中更新 docs/zh 和 docs/en 的相关操作说明与截图（或说明无需更新文档的原因）。入口改名、移动或合并时，已在文档和 changelog 中补充 旧入口 → 新入口 对照。

• 🤓 I have ensured that no new dependencies are introduced, OR if new dependencies are introduced, they have been added to the appropriate locations in requirements.txt and pyproject.toml.
  / 我确保没有引入新依赖库，或者引入了新依赖库的同时将其添加到 requirements.txt 和 pyproject.toml 文件相应位置。

• 😮 My changes do not introduce malicious code.
  / 我的更改没有引入恶意代码。

Summary by Sourcery

Fix Telegram bot mention handling for UTF-16 offsets so group messages and media captions wake the bot reliably.

Bug Fixes:

• Fix Telegram mention parsing when emoji or other non-BMP characters precede mentions by honoring Telegram’s UTF-16 entity offsets.
• Ensure bot mentions are correctly removed while preserving other mentions in messages and media captions.

Enhancements:

• Use Telegram SDK entity parsing for reliable mention extraction from text and captions.

Tests:

• Add regression coverage for emoji and non-ASCII prefixes, multiple mentions, commands, and mentions in photo, document, and video captions.