feat(api): add unauthenticated health endpoints

Add GET /api/v1/health/live and GET /api/v1/health/ready per ADR 0044.

- live returns a fixed 200 {"status":"live"} whenever the process serves.
- ready returns 200 {"status":"ready"} only when module startup has
  completed (and shutdown has not begun) and a database ping succeeds
  within 2s; otherwise a fixed 503 {"code":"NOT_READY"}.
- The ping runs on the shared pool as one simple-protocol message with
  a transaction-local statement_timeout, so PostgreSQL cancels a stalled
  statement; the pool discards the connection on failure.
- At most one ping is ever unsettled: probes share its outcome and, once
  its deadline passes, answer 503 immediately until it settles.
- Both routes set Cache-Control: no-store, accept GET only (405 with
  Allow: GET otherwise, HEAD included), never resolve a principal, and
  are mounted in app.ts beside, never inside, /api/v1/modules/.
- createApiApp gains a required `health` option; startApi supplies it
  and clears module readiness when shutdown begins.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/api/tests/module-display-routes.test.ts

@@ -38,6 +38,7 @@ import { moduleRealtimeBaseUrl } from "../src/module-realtime-routes.js";
 import { MODULE_UI_INVENTORY_PATH } from "../src/module-ui-inventory.js";
 import { moduleDisplayUiArtifactUrl } from "../src/module-ui-routes.js";
 import { createInMemoryDashboardStore } from "./support/in-memory-dashboard-store.js";
+import { readyHealth } from "./support/ready-health.js";
 import { moduleConfigurationOptionFor } from "./support/in-memory-module-configuration.js";
 import {
   createInMemoryModuleLifecycleStore,
@@ -198,6 +199,7 @@ async function install(options: InstallOptions): Promise<Installation> {
       store: fakeAuthorizationStore(),
     },
     dashboard: createInMemoryDashboardStore(),
+    health: readyHealth(),
     ...(moduleUi.listDisplays().length > 0 && options.withAssets !== false
       ? { displayHostAssets: options.assets ?? displayHostAssets }
       : {}),