Add sendPayload handler to Telegram outbound adapter to support
channel-specific data via the channelData pattern. This enables
features like inline keyboard buttons without custom ReplyPayload fields.
Implementation:
- Extract telegram.buttons from payload.channelData
- Pass buttons to sendMessageTelegram (already supports this)
- Follows existing sendText/sendMedia patterns
- Completes optional ChannelOutboundAdapter.sendPayload interface
This enables plugins to send Telegram-specific features (buttons, etc.)
using the standard channelData envelope pattern instead of custom fields.
Related: delivery system in src/infra/outbound/deliver.ts:324 already
checks for sendPayload handler and routes accordingly.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
