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/lib/events.ts

@@ -22,3 +22,15 @@ export interface SenchoOpenStackDetail {
   nodeId: number;
   stackName: string;
 }
+
+/** Tabs of the top-level Security view. Used by the nav state and by
+ *  cross-component navigate events that deep-link into a specific tab. */
+export type SecurityTab =
+  | 'overview'
+  | 'images'
+  | 'compose'
+  | 'secrets'
+  | 'policies'
+  | 'suppressions'
+  | 'history'
+  | 'scanner';

frontend/src/lib/severityStyles.ts

@@ -7,3 +7,30 @@ export const SEVERITY_ROW_TINT: Record<VulnSeverity, string> = {
   LOW: 'border-l-[3px] border-transparent',
   UNKNOWN: 'border-l-[3px] border-transparent',
 };
+
+/**
+ * Border/background/text classes for a severity pill. `CLEAN` is the all-zero
+ * state; `FINDINGS` is the amber "not clean but no vulnerability severity"
+ * state for a scan that has secrets or misconfigurations but zero CVEs (the
+ * stored highest_severity is derived from vulnerabilities only).
+ */
+export const SEVERITY_BADGE_CLASSES: Record<VulnSeverity | 'CLEAN' | 'FINDINGS', string> = {
+  CRITICAL: 'border-destructive/25 bg-destructive/8 text-destructive',
+  HIGH: 'border-warning/25 bg-warning/8 text-warning',
+  MEDIUM: 'border-warning/25 bg-warning/8 text-warning',
+  LOW: 'border-border bg-muted/30 text-muted-foreground',
+  UNKNOWN: 'border-border bg-muted/20 text-muted-foreground',
+  CLEAN: 'border-success/25 bg-success/8 text-success',
+  FINDINGS: 'border-warning/25 bg-warning/8 text-warning',
+};
+
+/** Leading state-dot color for a severity pill. */
+export const SEVERITY_DOT_CLASSES: Record<VulnSeverity | 'CLEAN' | 'FINDINGS', string> = {
+  CRITICAL: 'bg-destructive',
+  HIGH: 'bg-warning',
+  MEDIUM: 'bg-warning',
+  LOW: 'bg-muted-foreground/60',
+  UNKNOWN: 'bg-muted-foreground/40',
+  CLEAN: 'bg-success',
+  FINDINGS: 'bg-warning',
+};