Feature Request

Description:
Add support for sending Telegram messages silently (without notification sound) via the message tool.

Use Case:
When sending automated notifications, heartbeat updates, or non-urgent messages, it would be useful to deliver them without triggering a notification sound on the recipient's device.

Telegram API:
The Telegram Bot API supports disable_notification parameter on all send methods (sendMessage, sendPhoto, etc.). The underlying grammy library already supports this.

Proposed Implementation:

1. Add silent (boolean) parameter to the message tool schema
2. Pass it through telegramOutbound in channels/plugins/outbound/telegram.js
3. Include disable_notification: opts.silent in the send options in telegram/send.js

Example usage:

message(action="send", target="...", message="...", silent=true)

Thanks!