Add a new channel extension for Plivo SMS/MMS messaging, enabling
universal phone-based access to Clawdbot from any device.
Features:
- Two-way SMS messaging via Plivo API
- MMS media support (images, videos, documents)
- Quick command shortcuts (e.g., "cal" -> "show my calendar")
- Auto-configuration of Plivo webhooks on startup
- Multi-account support
- DM policies (pairing, allowlist, open)
Implements ideas 3.1, 3.3, 3.4, 3.7 from PLIVO_INTEGRATION_IDEAS.md:
- 3.1 SMS Channel Adapter
- 3.3 Quick Commands via SMS
- 3.4 MMS Media Sharing
- 3.7 Critical Alerts via SMS
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
