The Deploy workflow on main failed because .cargo/config.toml requires
the mold linker, but deploy.yml only installed lld. The earlier fix
commit only updated push.yml, missing deploy.yml.
Replace Nix flake with mise for toolchain management, treefmt for
formatting, prek for pre-commit hooks, and a Dockerfile for container
builds. Update CI workflows to use jdx/mise-action instead of Nix.
Add system dependency instructions to README.md and CLAUDE.md.
Merge separate lint and test jobs into a single check job so clippy's
compilation artifacts are reused by tests. Add actions/cache for the
Cargo target directory and registry to enable incremental builds across
runs. Drop unnecessary fetch-depth: 0 from CI jobs.
The container image is tagged with the package version from flake.nix,
not the git short hash. Read the version from Cargo.toml so the
docker tag command references the correct source image.
