The repo shipped no committed dev environment, so building required a
working personal Nix/home-manager setup on PATH. Add a flake providing
the full toolchain pinned via flake.lock: stable rust (per
rust-toolchain.toml) + rustfmt/clippy/rust-analyzer, clang + mold
(the linker the cargo config expects), nodejs 22, pnpm 9, tmux, git,
and just.
The shell sets the per-target linker/rustflags so it is self-contained
and hermetic: cargo takes the first matching rustflags source (env >
target > build), so this replaces any global `[build] rustflags` — in
particular the nightly-only `-Z threads=8` that would otherwise break
the stable toolchain — while keeping the fast mold link.
Use with `nix develop` or `direnv allow` (.envrc).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
