Implement headlamp-tns-csi-plugin

Full plugin implementation with 6 pages, K8s resource filtering,
Prometheus metrics parsing, kbench benchmark runner, and 67 unit tests.

## Pages
- Overview: driver health, storage summary, protocol distribution chart, non-Bound PVC alerts
- Storage Classes: tns-csi SC table with slide-in detail panel + protocol notes
- Volumes: PV table with full CSI attribute detail panel
- Snapshots: VolumeSnapshot CRDs with graceful degradation if not installed
- Metrics: Prometheus text format parser + WebSocket/Volume/CSI operation cards
- Benchmark: kbench Job+PVC lifecycle, FIO log parser, past benchmarks list

## API modules
- k8s.ts: typed resource shapes, filtering helpers, formatting utilities
- metrics.ts: Prometheus text format parser, tns-csi metric extraction
- kbench.ts: Job/PVC manifests, lifecycle management, FIO summary parser
- TnsCsiDataContext.tsx: shared React context with memoized filtered resources

## Quality
- TypeScript strict mode, zero any, discriminated union for benchmark state
- 67 tests passing (vitest + @testing-library/react)
- registerDetailsViewSection injects TNS-CSI details on PVC pages
- Graceful degradation for missing CSIDriver and VolumeSnapshot CRDs

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/TnsCsiDataContext.test.tsx

@@ -0,0 +1,51 @@
+import { renderHook } from '@testing-library/react';
+import React from 'react';
+import { describe, expect, it, vi } from 'vitest';
+
+// Mock headlamp plugin APIs before importing the module under test
+vi.mock('@kinvolk/headlamp-plugin/lib', () => ({
+  ApiProxy: {
+    request: vi.fn().mockResolvedValue({ items: [] }),
+  },
+  K8s: {
+    ResourceClasses: {
+      StorageClass: {
+        useList: vi.fn(() => [[], null]),
+      },
+      PersistentVolume: {
+        useList: vi.fn(() => [[], null]),
+      },
+      PersistentVolumeClaim: {
+        useList: vi.fn(() => [[], null]),
+      },
+    },
+  },
+}));
+
+import { TnsCsiDataProvider, useTnsCsiContext } from './TnsCsiDataContext';
+
+describe('useTnsCsiContext', () => {
+  it('throws when used outside TnsCsiDataProvider', () => {
+    const spy = vi.spyOn(console, 'error').mockImplementation(() => {});
+
+    expect(() => {
+      renderHook(() => useTnsCsiContext());
+    }).toThrow('useTnsCsiContext must be used within a TnsCsiDataProvider');
+
+    spy.mockRestore();
+  });
+
+  it('returns context value when inside TnsCsiDataProvider', async () => {
+    const wrapper = ({ children }: { children: React.ReactNode }) => (
+      <TnsCsiDataProvider>{children}</TnsCsiDataProvider>
+    );
+
+    const { result } = renderHook(() => useTnsCsiContext(), { wrapper });
+
+    expect(result.current).toBeDefined();
+    expect(result.current.storageClasses).toBeInstanceOf(Array);
+    expect(result.current.persistentVolumes).toBeInstanceOf(Array);
+    expect(result.current.persistentVolumeClaims).toBeInstanceOf(Array);
+    expect(typeof result.current.refresh).toBe('function');
+  });
+});