feat(GRO-984): outbound SMS persistence

- Add sendMessage() to outbound.ts with opt-in check, find/create conversation, queued→sent/failed transitions
- Add unit tests for success, opt-out suppression, missing tenant phone
- Add uuid and @types/uuid to package.json dependencies
- sms.ts unchanged (already Telnyx transport only on dev)

PR for GRO-1016 (replacement for #379)
Closes GRO-984

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/package.json

@@ -24,6 +24,7 @@
     "nodemailer": "^6.9.16",
     "stripe": "^22.0.0",
     "telnyx": "^1.23.0",
+    "uuid": "^11.0.5",
 
     "zod": "^4.3.6"
   },
@@ -31,6 +32,7 @@
     "@types/node": "^22.10.7",
     "@types/node-cron": "^3.0.11",
     "@types/nodemailer": "^6.4.17",
+    "@types/uuid": "^10.0.0",
     "@vitest/coverage-v8": "^3.2.4",
     "eslint": "^9.18.0",
     "tsx": "^4.19.2",