fix: resolve bugs in benchmark lifecycle, snapshot filtering, and dark mode

- Fix PVC bind loop leak on unmount via cancellation ref
- Fix DeleteOptions body structure for proper foreground propagation
- Filter snapshots to tns-csi driver only (was showing all drivers)
- Fix stale closures in Escape key handlers with useCallback
- Add loading state to cleanup delete button, remove window.confirm/alert
- Use CSS custom properties for protocol chart colors (dark mode support)
- Fix all 35 ESLint warnings (import sort, indent, boolean attrs)

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

src/components/MetricsPage.tsx

@@ -11,9 +11,9 @@ import {
   StatusLabel,
 } from '@kinvolk/headlamp-plugin/lib/CommonComponents';
 import React, { useCallback, useEffect, useState } from 'react';
-import { useTnsCsiContext } from '../api/TnsCsiDataContext';
 import type { TnsCsiMetrics } from '../api/metrics';
 import { fetchControllerMetrics, formatBytes, groupByLabel, sumSamples } from '../api/metrics';
+import { useTnsCsiContext } from '../api/TnsCsiDataContext';
 
 function formatAuditTime(iso: string): string {
   const date = new Date(iso);