Add LINE Messaging API as the 9th messaging channel using HTTP Webhook.
Supports text/image/audio messages, group chat @mention detection,
reply with quote, and loading animation.
- No external SDK required (standard library only)
- HMAC-SHA256 webhook signature verification
- Reply Token (free) with Push API fallback
- Group chat: respond only when @mentioned
- Quote original message in replies using quoteToken
Closes#146
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add Slack as a messaging channel using Socket Mode (WebSocket), bringing
the total supported channels to 8. Features include bidirectional
messaging, thread support with per-thread session context, @mention
handling, ack reactions (👀/✅), slash commands,
file/attachment support with Groq Whisper audio transcription, and
allowlist filtering by Slack user ID.
Closes#31
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
