feat: consolidate dashboard pages, fix namespace links, add tests

Merge Overview and Full Audit into a single dashboard page that always
shows the skipped check count. Fix namespace link 404s by using
Headlamp's Link component (which generates cluster-prefixed URLs)
instead of raw react-router-dom Link. Add vitest unit tests for all
polaris.ts utility functions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/index.tsx

@@ -28,14 +28,6 @@ registerSidebarEntry({
   icon: 'mdi:view-dashboard',
 });
 
-registerSidebarEntry({
-  parent: 'polaris',
-  name: 'polaris-full',
-  label: 'Full Audit',
-  url: '/polaris/full-audit',
-  icon: 'mdi:clipboard-text-search',
-});
-
 registerSidebarEntry({
   parent: 'polaris',
   name: 'polaris-namespaces',
@@ -53,19 +45,7 @@ registerRoute({
   exact: true,
   component: () => (
     <PolarisDataProvider>
-      <DashboardView includeSkipped={false} />
-    </PolarisDataProvider>
-  ),
-});
-
-registerRoute({
-  path: '/polaris/full-audit',
-  sidebar: 'polaris-full',
-  name: 'polaris-full-audit',
-  exact: true,
-  component: () => (
-    <PolarisDataProvider>
-      <DashboardView includeSkipped />
+      <DashboardView />
     </PolarisDataProvider>
   ),
 });