fix(settings): use frontend build version

[itsDNNS]

Summary

• use the frontend build version for Settings/About when it is baked into the frontend image
• pass the derived app version into the frontend Docker build so split frontend/backend deployments show the active frontend build
• scope the release-check cache by the displayed version to avoid stale update banners after upgrades

Tests

• cd frontend && npm test -- --runTestsByPath __tests__/lib/version.test.js __tests__/components/AboutTab.test.js --runInBand
• python3 -m pytest -q tests/test_docker_workflow.py
• cd frontend && npm run build
• BASE_URL=http://127.0.0.1:3000 npx playwright test e2e/tests/about-version.spec.js --project="Desktop Chrome" --project="Mobile Chrome" --reporter=line
• git diff --check