fix: resolve CI failures for PR #583
Add CI-specific timeout multipliers (3×) to security E2E tests
emergency-token.spec.ts, combined-enforcement.spec.ts
waf-enforcement.spec.ts, emergency-server.spec.ts
Add missing data-testid="multi-file-import-button" to ImportCaddy.tsx
Add accessibility attributes to ImportSitesModal.tsx (aria-modal, aria-labelledby)
Add ProxyHostServiceInterface for mock injection in tests
Fix TestImportHandler_Commit_UpdateFailure (was skipped)
Backend coverage: 43.7% → 86.2% for Commit function
Resolves: E2E Shard 4 failures, Frontend Quality Check failures, Codecov patch coverage
a7b3cf38a2