feat: add tooltip to skipped count explaining limitation

The skipped count only reflects checks with Severity=ignore from
the Polaris API. Annotation-based exemptions (e.g.,
polaris.fairwinds.com/*-exempt) are not included because:

1. Exempted checks are completely omitted from results.json
2. The Polaris dashboard UI counts exemptions client-side by
   querying Kubernetes resources for annotations
3. Our plugin only has access to the processed audit results

Added HTML title tooltip to explain this limitation to users.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

src/components/DashboardView.tsx

@@ -51,7 +51,14 @@ function OverviewSection(props: { data: AuditData; counts: ResultCounts }) {
               name: 'Danger',
               value: <StatusLabel status="error">{counts.danger}</StatusLabel>,
             },
-            { name: 'Skipped', value: String(counts.skipped) },
+            {
+              name: 'Skipped',
+              value: (
+                <span title="Only counts checks with Severity=ignore. Annotation-based exemptions are not included.">
+                  {counts.skipped}
+                </span>
+              ),
+            },
           ]}
         />
       </SectionBox>

src/components/NamespaceDetailView.tsx

@@ -120,7 +120,11 @@ export default function NamespaceDetailView() {
             },
             {
               name: 'Skipped',
-              value: String(counts.skipped),
+              value: (
+                <span title="Only counts checks with Severity=ignore. Annotation-based exemptions are not included.">
+                  {counts.skipped}
+                </span>
+              ),
             },
           ]}
         />