Merge release/delivery (IAM single sign-on) into the triage work

Brings the four release/delivery commits (IAM SSO for the admin panel,
both apps and the API; IAM env in docker-compose) onto fix/issues-triage.

Conflicts:
- customer-auth.service.ts imports: both kept.
- both apps' api/client.ts: both kept (AccountingBalance/WageQuote, and
  iamAppUrl).
- all build output (admin-panel, user-app, user-app-v2 dist, and the api
  release bundle): rebuilt from the merged source instead of picking a
  side.

Fixed while verifying:
- The IAM change calls iam.browserBootstrapUrl after every login, but
  the identity-service stand-ins in three test files lacked it. 15 tests
  failed on release/delivery itself.
- SMS relay: SMS_RELAY_PLATFORM was read but never sent, so the gateway
  never got `platform` (documented body: phone, host, text, platform).
  relayConfig() now returns it ("default" → null) and the request carries
  it. sms.service.spec now passes.

All 249 API tests pass; the three front-ends type-check and build.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/release/vendor/.prisma/client/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "prisma-client-e72c5c915e96796902913fde6ec160a337ad8fec683314696d8bd7a12ac26468",
+  "name": "prisma-client-9161dfb7f2a3ada2b72c27c7a91664048e7f0e5d5d265a0abff1e443711c8388",
   "main": "index.js",
   "types": "index.d.ts",
   "browser": "index-browser.js",