Add a Hatch build hook that downloads JS/CSS dependencies during wheel
builds and rewrites base.html to use local paths. This allows the web UI
to work in environments without internet access.
- Add data-vendor attributes to base.html for declarative asset mapping
- Download htmx, tailwind, daisyui, and xterm.js during build
- Bundle LICENSES.txt with attribution for vendored dependencies
- Source HTML keeps CDN links for development; wheel has local paths
