Adds support for sending multiple photos/videos as a Telegram album:
- New `sendMediaGroupTelegram` function in telegram/send.ts
- Telegram outbound adapter now uses media groups for 2-10 images
- Message tool accepts `mediaUrls` array parameter
- Albums display as a single grouped message in Telegram
Usage:
```
message(action='send', target='123', mediaUrls=['url1.jpg', 'url2.jpg'], caption='My album')
```
Limitations:
- Telegram albums don't support inline buttons (sent as follow-up)
- Only photos and videos supported (no documents in albums)
- 2-10 items required for album mode
