feat: initial kube-vip Headlamp plugin

Headlamp plugin providing visibility into kube-vip virtual IP and load
balancer deployments. Features:

- Overview dashboard with deployment status, VIP mode, leader election
- Services page with LoadBalancer VIP assignments and detail panels
- Nodes page showing kube-vip pod status and leader designation
- Configuration page with DaemonSet config, IP pools, leases
- Service detail section injected into native Headlamp Service views

Read-only plugin — no cluster write operations. Uses standard K8s
resources (no CRDs): Services, Nodes, Pods, DaemonSets, Leases,
ConfigMaps with kube-vip.io/* annotations.

74 tests across 7 test files. All tsc/lint/format/test checks pass.

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

vitest.config.mts

@@ -0,0 +1,10 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'jsdom',
+    setupFiles: ['./vitest.setup.ts'],
+    exclude: ['e2e/**', 'node_modules/**'],
+  },
+});