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>

CONTRIBUTING.md

@@ -0,0 +1,36 @@
+# Contributing
+
+Contributions are welcome! Please follow these guidelines.
+
+## Development Setup
+
+```bash
+git clone https://github.com/privilegedescalation/headlamp-kube-vip-plugin.git
+cd headlamp-kube-vip-plugin
+npm install
+npm start
+```
+
+## Before Submitting a PR
+
+```bash
+npm run tsc          # TypeScript type check
+npm run lint         # ESLint
+npm run format:check # Prettier
+npm test             # All tests must pass
+```
+
+## Code Style
+
+- TypeScript strict mode (no `any`)
+- Functional React components only
+- All UI from `@kinvolk/headlamp-plugin/lib/CommonComponents`
+- Tests with vitest + @testing-library/react
+
+## Commit Messages
+
+Use conventional commit format:
+- `feat:` new features
+- `fix:` bug fixes
+- `chore:` maintenance
+- `docs:` documentation