feat: expose multi-host runtime readiness

docs/SCALABILITY_PROFILES.md

@@ -39,6 +39,9 @@ The Ops API reports:
 - runtime node identity, role, software/module composition, queues, heartbeat,
   stale state, and drain state
 - configured versus active API and worker replica counts
+- active worker-pool names, exact queue coverage, and missing queue owners
+- release/module-composition skew and software-version skew across active nodes
+- rendered PostgreSQL connection peak, declared server limit, and operator reserve
 - recovery operation status, mode, checkpoint count, and last update
 
 These values are intentionally diagnostic. They do not replace deployment
@@ -54,6 +57,13 @@ manual-intervention record means an operator must repair the current release or
 restore a separately verified coordinated backup. Ops does not convert that
 state into a safe rollback.
 
+For the `shared` profile, missing expected replicas, release/composition skew,
+unserved queues, or an invalid PostgreSQL connection budget are readiness
+errors. Stale historical records remain visible, but cannot downgrade one of
+those errors to a warning. A database budget at or above 80 percent is reported
+as a warning so operators retain room for measured bursts and administrative
+connections.
+
 `deployment_security` is inactive for local/test profiles. In staging or pilot
 profiles it warns when secure cookies or CORS origins still look local. In
 production it becomes readiness-critical because TLS certificates, proxy