fix: add :80 port to dashboard proxy constant

The POLARIS_DASHBOARD_PROXY constant was missing :80, causing
dashboard links in the UI to fail with "no endpoints available".
This matches the fix already applied to POLARIS_API_PATH.

Fixes external dashboard link in namespace detail view.

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/api/polaris.ts

@@ -146,7 +146,7 @@ export function setRefreshInterval(seconds: number): void {
 // --- Polaris dashboard proxy URL ---
 
 export const POLARIS_DASHBOARD_PROXY =
-  '/api/v1/namespaces/polaris/services/polaris-dashboard/proxy/';
+  '/api/v1/namespaces/polaris/services/polaris-dashboard:80/proxy/';
 
 // --- Score computation ---