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>

CLAUDE.md

@@ -0,0 +1,93 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project
+
+Headlamp plugin for kube-vip virtual IP and load balancer visibility. Read-only — monitors kube-vip DaemonSet/pods, LoadBalancer services, nodes, IP pools, and leader election. No cluster write operations.
+
+- **Plugin name**: `kube-vip`
+- **Target**: Headlamp >= v0.26
+- **Data sources**: kube-vip DaemonSet/pods in `kube-system`, Services (type:LoadBalancer), Nodes, Leases, `kubevip` ConfigMap
+- **Reference plugin**: `../headlamp-polaris-plugin`
+
+## Commands
+
+```bash
+npm start          # dev server with hot reload
+npm run build      # production build
+npm run package    # package for headlamp
+npm run tsc        # TypeScript type check (no emit)
+npm run lint       # ESLint
+npm run lint:fix   # ESLint with auto-fix
+npm run format     # Prettier write
+npm run format:check # Prettier check
+npm test           # vitest run
+npm run test:watch # vitest watch mode
+```
+
+All tests and `tsc` must pass before committing.
+
+## Architecture
+
+```
+src/
+├── index.tsx                         # Plugin entry: registerRoute, registerSidebarEntry, registerDetailsViewSection
+├── test-helpers.tsx                  # Shared test utilities and fixtures
+├── api/
+│   ├── k8s.ts                        # Types + helpers (Services, Nodes, Pods, DaemonSets, Leases, ConfigMaps)
+│   └── KubeVipDataContext.tsx        # Shared React context provider
+└── components/
+    ├── OverviewPage.tsx               # Dashboard: deployment status, cluster summary, VIP overview
+    ├── ServicesPage.tsx               # LoadBalancer services with VIP assignments and detail panel
+    ├── NodesPage.tsx                  # Nodes with kube-vip pod status and leader election
+    ├── ConfigPage.tsx                 # DaemonSet config, IP pools, leases, pod details
+    ├── ServiceDetailSection.tsx       # Injected into Headlamp Service detail view
+    └── __mocks__/
+        └── commonComponents.ts       # Test mocks for headlamp CommonComponents
+```
+
+## Data flow
+
+`KubeVipDataContext.tsx` uses **two fetching strategies**:
+
+1. **Headlamp hooks** (`K8s.ResourceClasses.*.useList()`) — for Services and Nodes.
+2. **`ApiProxy.request()`** — for kube-vip DaemonSet, pods (with label selector fallback for static pods), cloud-provider pods, Leases, and the `kubevip` ConfigMap.
+
+kube-vip uses **no CRDs**. All state comes from standard Kubernetes resources and `kube-vip.io/*` annotations on Services.
+
+## Key constants (src/api/k8s.ts)
+
+- Namespace: `kube-system`
+- DaemonSet name: `kube-vip-ds`
+- Cloud provider name: `kube-vip-cloud-provider`
+- ConfigMap name: `kubevip`
+- Annotation prefix: `kube-vip.io/`
+- Pod selector: `app.kubernetes.io/name=kube-vip-ds`
+- Cloud provider selector: `app=kube-vip-cloud-provider`
+- Metrics port: `2112`
+
+## Code conventions
+
+- Functional React components only — no class components
+- All imports from `@kinvolk/headlamp-plugin/lib` and `@kinvolk/headlamp-plugin/lib/CommonComponents`
+- No additional UI libraries (no MUI direct imports, no Ant Design, etc.)
+- TypeScript strict mode — no `any`, use `unknown` + type guards at API boundaries
+- Context provider (`KubeVipDataProvider`) wraps each route component in `index.tsx`
+- Tests: vitest + @testing-library/react, mock with `vi.mock('@kinvolk/headlamp-plugin/lib', ...)`
+- `vitest.setup.ts` provides a spec-compliant `localStorage` shim for Node 22+ compatibility
+
+## Testing
+
+Mock pattern for headlamp APIs:
+```typescript
+vi.mock('@kinvolk/headlamp-plugin/lib', () => ({
+  ApiProxy: { request: vi.fn().mockResolvedValue({ items: [] }) },
+  K8s: {
+    ResourceClasses: {
+      Service: { useList: vi.fn(() => [[], null]) },
+      Node: { useList: vi.fn(() => [[], null]) },
+    },
+  },
+}));
+```