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.)

backend/internal/adminconsole/assets/console.css

@@ -47,3 +47,25 @@ h1 { font-size: 1.4rem; margin: 0 0 0.4rem; }
 .card:hover { background: var(--panel-hi); text-decoration: none; }
 .card h2 { font-size: 1.05rem; margin: 0 0 0.3rem; color: var(--accent); }
 .card p { margin: 0; color: var(--ink-dim); font-size: 0.9rem; }
+
+.panel {
+  padding: 0.9rem 1.1rem;
+  background: var(--panel);
+  border: 1px solid var(--line);
+  border-radius: 8px;
+  margin-bottom: 1rem;
+}
+.panel h2 { font-size: 1rem; margin: 0 0 0.6rem; color: var(--ink); }
+.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; margin-bottom: 1rem; }
+.grid .panel { margin-bottom: 0; }
+.kv { list-style: none; margin: 0; padding: 0; }
+.kv li { padding: 0.15rem 0; color: var(--ink-dim); }
+.counts { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
+.counts td { padding: 0.2rem 0; border-bottom: 1px solid var(--line); color: var(--ink-dim); }
+.counts td.num { text-align: right; color: var(--ink); font-variant-numeric: tabular-nums; }
+.bignum { font-size: 1.6rem; margin: 0; color: var(--ink); }
+.note { color: var(--ink-dim); font-style: italic; margin: 0.2rem 0; }
+.errors { border-color: var(--danger); }
+.errors ul { margin: 0; padding-left: 1.1rem; color: var(--danger); }
+.ok { color: var(--ok); }
+.bad { color: var(--danger); }