feat(admin-console): Stage 2 — dashboard monitoring

Turn the console landing page into an operational dashboard.

- new internal/opsstatus: read-only Postgres projection via go-jet — ping +
  per-status COUNT/GROUP BY on runtime_records, mail_deliveries,
  notification_routes, and a malformed-intent count; degrades per-probe into
  Snapshot.Errors rather than failing the page
- dashboard renders backend readiness, database health, the three status
  tables, the malformed count, and any collection errors; falls back to a
  "monitoring not wired" note when no reader is injected
- AdminConsoleHandlers now takes an AdminConsoleDeps struct (Monitor + Ready
  added) so later stages add service refs without churning the signature

Tests: opsstatus store test against a Postgres testcontainer (empty schema +
one enqueued delivery); dashboard render tests with a fake reader (with and
without monitoring).

Docs: ARCHITECTURE 14.1 + FUNCTIONAL 10.2.1 (+ru) describe the dashboard.
(Prometheus /metrics exporters were already enabled in dev-deploy in Stage 1.)

docs/FUNCTIONAL.md

@@ -1178,6 +1178,12 @@ limiting and request limits as the public API, and it carries an
 anti-CSRF token on every change. The JSON admin API stays internal to
 the deployment.
 
+The console landing page is a dashboard that summarises operational
+health: whether the backend is ready and the database reachable, how many
+game runtimes sit in each state, and the depth of the mail and
+notification queues. It is a read-only point-in-time view for quick
+triage, not a metrics history.
+
 ### 10.3 Admin account management
 
 Existing admins can list other admins, create new ones, look up a