feat: add dedicated Security page and policy-pack foundation (#1362)

* feat: add dedicated Security page and policy-pack foundation

Bring vulnerability scanning, scan history, suppressions, Compose risks,
secrets, policy packs, and scanner setup into one node-scoped Security
command center instead of scattering them across Resources and Settings.

- New top-level Security view with Overview, Images, Compose risks,
  Secrets, Policies, Suppressions, History, and Scanner setup tabs
  (status masthead + signal rail; controlled tabs with deep-link support).
- Backend: GET /security/overview rollup and GET /security/policy-packs
  static catalog (auth-only, Community). DatabaseService gains an uncapped
  scan-status count and a node-eligible block-policy count, and
  getImageScanSummaries now projects secret and misconfig counts.
- Reuse existing surfaces: the scan-history sheet, the control-governed
  suppression and acknowledgement panels, and the scan-detail sheet (now
  with an initial-tab prop so it opens on the matching finding type).
- Extract a shared SeverityBadge (from Resources) and a TrivyManager
  (from Settings) so both surfaces render identical controls.
- Resources "Scan history" now links into the Security page History tab.
- Docs for the new Security surface and tests for the new endpoints,
  helpers, nav wiring, and tabs.

* refactor: consolidate scanner and policy management onto the Security page

Remove the Settings "Vulnerability Scanning" section now that the Security
page covers the same ground, with every option preserved:

- Scanner install / update / uninstall / auto-update live on the Scanner setup
  tab (TrivyManager).
- Scan policies, the honor-suppressions toggle, and the replica
  managed-by-control / demote controls move into a new ScanPolicyManager on the
  Policies tab (paid; Community sees only the policy-pack catalog).
- CVE suppressions and acknowledgements remain on the Suppressions tab.

Wiring removed: the registry section and the now-empty Security settings group,
the SectionId, the SettingsSectionContent case and the isPaid prop it was the
sole consumer of, and SecuritySection itself. The dashboard configuration-status
"Vulnerability scanning" row now navigates to the Security page Policies tab.

Docs that pointed at "Settings -> Security -> Vulnerability Scanning" are swept
to the relevant Security page tabs.

* fix: harden Security page scanner refresh, policy-load errors, and secret-only badges

Address independent-review findings on the Security page:

- Scanner setup now refreshes Trivy state when the active node changes, so the
  displayed scanner status matches the node TrivyManager's actions target (both
  follow x-node-id). Previously, switching nodes on the tab left stale state.
- ScanPolicyManager surfaces an explicit error state on a failed policy fetch
  instead of falling through to a false "No scan policies configured".
- The shared SeverityBadge and the Images findings column no longer label a scan
  "clean" when it has secrets or misconfigurations but no CVE severity
  (highest_severity is derived from vulnerabilities only); they show a "Findings"
  state and the secret/misconfig counts instead.
- The Overview enforcement note points to the Policies tab, not the removed
  Settings section.
- The History tab auto-opens the scan-history sheet only on a deep-link (mount
  with the History tab active), not on every manual tab selection.

Adds tests for the badge secret/misconfig state and the policy-load error state.

frontend/src/components/EditorLayout/ViewRouter.tsx

@@ -13,6 +13,7 @@ import HomeDashboard from '../HomeDashboard';
 import type { NotificationItem } from '../dashboard/types';
 import type { ScheduleTaskPrefill } from '../ScheduledOperationsView';
 import type { ActiveView } from './hooks/useViewNavigationState';
+import type { SecurityTab } from '@/lib/events';
 
 // Paid-tier views and the security-history overlay are loaded on demand.
 // Their internal PaidGate / CapabilityGate wrappers render
@@ -39,6 +40,9 @@ const AuditLogView = lazy(() =>
 );
 const ScheduledOperationsView = lazy(() => import('../ScheduledOperationsView'));
 const AutoUpdateReadinessView = lazy(() => import('../AutoUpdateReadinessView'));
+const SecurityView = lazy(() =>
+    import('../SecurityView').then(m => ({ default: m.SecurityView })),
+);
 
 // Sized for the main workspace area (flex-1 with p-6 padding). Visible
 // only during the brief window between an unlocked view's chunk request
@@ -81,6 +85,8 @@ export interface ViewRouterProps {
     onNavigateToStack: (stackFile: string) => void;
     onOpenSettingsSection: (section: SectionId) => void;
     onClearNotifications: () => void;
+    securityTab: SecurityTab;
+    onSecurityTabChange: (tab: SecurityTab) => void;
     // Render slot for the inline editor view. Kept as a callback so the
     // (large) editor JSX is only allocated when activeView === 'editor',
     // not on every parent render that lands on a different view.
@@ -104,6 +110,8 @@ export function ViewRouter({
     onNavigateToStack,
     onOpenSettingsSection,
     onClearNotifications,
+    securityTab,
+    onSecurityTabChange,
     renderEditor,
 }: ViewRouterProps): ReactNode {
     const { can } = useAuth();
@@ -121,6 +129,16 @@ export function ViewRouter({
     if (activeView === 'resources') {
         return <ResourcesView />;
     }
+    if (activeView === 'security') {
+        // Node-scoped (not hub-only): scan/scanner data follows the active node
+        // like Resources. The page itself is Community; per-tab gates handle
+        // capability-missing nodes and the local-control governance tabs.
+        return (
+            <LazyView>
+                <SecurityView activeTab={securityTab} onTabChange={onSecurityTabChange} />
+            </LazyView>
+        );
+    }
     if (activeView === 'host-console') {
         // Mirror the backend RBAC gate (system:console, admin-only). The nav
         // item is already admin-gated; this stops a non-admin who reaches the