Change build script to output to public/dist instead of ../backend/web/static/dist.
The Dockerfile copies from frontend/public/, so the previous path caused builds
to output to a non-existent directory, resulting in stale files being deployed.
Also add mkdir -p to dev script for robustness.
Embed frontend build output directly into Go binary using //go:embed.
This removes runtime dependency on ../frontend/public/ path and
simplifies Docker builds by serving assets from embedded filesystem.
- Add backend/web/embed.go with embed.FS directive
- Update server to serve from embedded static assets
- Update Makefile to copy frontend build to web/static/
- Update Dockerfile for simplified multi-stage build
- Update frontend package.json output paths
- Remove custom 'oc' command from flake.nix dev shell
- Upgrade to Tailwind CSS v4.2.0 with explicit CLI dependency
- Add @tailwindcss/cli and tailwindcss as devDependencies
- Update build scripts to use bunx @tailwindcss/cli
- Include new transitive dependencies for enhanced CSS processing
