[ rhonda-rodododo/llamenos ] docs: epics 42-46 — multi-channel messaging, reporter role, encrypted uploads

Epic 42: Messaging architecture — MessagingAdapter interface, ConversationDO,
  threaded conversations, WebSocket events, webhook routing
Epic 43: SMS channel — adapters for all 5 providers, auto-response, MMS,
  provider message cleanup for privacy
Epic 44: WhatsApp Business — Cloud API messaging + Calling API voice via
  WebRTC/SIP, template messages, 24h window handling
Epic 45: Signal channel — signal-cli-rest-api bridge, voice message
  transcription, health monitoring, graceful degradation
https://github.com/rhonda-rodododo/llamenos/commit/b40c9581f66ca5eed7543aebc544e894cbd866ff