feat: multi-arch Docker image (amd64 + arm64) (#57)

Use mise exec in pre-commit hooks (#56)

Auto-fit setlist font size to target page count (#52) (#53)

- Add --pages flag (default 2) to generate list command
- Binary search on font size (10px-60px) to maximize text size
  while fitting within the target page count
- --font-size flag overrides auto-fit when explicitly set
- Refactor convert package: extract HTMLToPDFBytes and PageCount

Revert to dockers (from dockers_v2) for Docker image builds (#51)

dockers_v2 uses buildx which doesn't support the simple binary
copy pattern used in the Dockerfile. The classic dockers approach
works correctly for this use case.

Bugfixes

support for markdown sheet sources

better section headers

section headers

add delete command

add delete command