feat(GRO-106): portal Communication tab — real backend

- Added GET /portal/conversation and GET /portal/conversation/messages endpoints
- Created Communication.api.ts with typed fetchers and React hooks
- Rewired Communication.tsx to use real API, removed mock data
- Added composer-disabled bar with "Reply from your phone" tooltip
- Added conversation route tests to portal.test.ts

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

packages/db/migrations/meta/_journal.json

@@ -222,7 +222,7 @@
     {
       "idx": 31,
       "version": "7",
-      "when": 1778818472097,
+"when": 1778818472097,
       "tag": "0032_staff_read_at",
       "breakpoints": true
     }