Release MultiSpeed 1.1.0

[dude2k]

What changed

• reject malformed boolean environment configuration
• add a privilege-separated workflow that refreshes embedded frontend assets for eligible Dependabot npm pull requests
• generate TypeScript API models from OpenAPI and enforce drift checks in CI
• add opt-in Prometheus/OpenMetrics metrics at /metrics
• add automated WCAG A/AA coverage and fix the detected labeling and contrast issues
• update documentation, embedded assets, and release metadata for MultiSpeed 1.1.0

Why

These changes make configuration failures explicit, reduce dependency-update maintenance, keep frontend contracts synchronized with the API, improve operational observability, and prevent accessibility regressions.

Validation

• Go race tests, vet, build, and govulncheck
• frontend lint, TypeScript check, 62 unit tests, and production build
• 6 Playwright end-to-end tests, including 5 axe accessibility scans
• OpenAPI lint and generated-type drift check
• GitHub Actions workflow lint
• npm production dependency audit
• production Docker build and embedded-asset reproducibility check

Release note

The version is prepared as 1.1.0. The v1.1.0 tag should be created only after this PR is merged and all required checks pass on main, as enforced by the release workflow.