v0.1.0

feat: dark/light theme, reproducible builds, verifiable builds docs

- Add dark/light theme with system preference detection and manual toggle
- Add reproducible build pipeline: SRI injection, SHA-256 build manifests
- Add Dockerfile.build for deterministic Docker builds
- Add CI/CD workflow (GitHub Actions) for tagged releases with manifest artifacts
- Add verify-build.cjs script for comparing local builds against production
- Expand verifiable builds documentation in docs and self-hosting pages
- Update README with new features, verifying builds section, correct repo URL
- Add .nvmrc (Node 22.14.0), .yarnrc, .dockerignore
- Update CSS variables for theme support across all components