The /style.css route 500'd in production because style.css is
gitignored and the Dockerfile never produced it: only main.py and
templates/ were copied into the image.
Mirror the myice Dockerfile by building the CSS in the builder stage:
copy the tailwind input files, download the standalone Tailwind CLI
(arch-aware for x64/arm64), and compile style.css. The artifact is
then copied into the runtime stage.
build-css.sh is kept for local dev but not used in Docker because its
#!/bin/bash shebang and pipefail are incompatible with alpine's sh.
herel
