Root cause: `option_env!("FOXHUNT_BUILD_VERSION")` in common/build_info.rs
was a compile-time macro tracked by cargo fingerprints (Rust 1.80+). Every
pipeline run with a new tag invalidated `common` → cascading rebuild of all
38 dependent workspace crates, even when zero source files changed.
Fix: replace `option_env!()` with `std::env::var()` (runtime LazyLock). Cargo
no longer tracks the version env var, so `common` only recompiles when its
source actually changes.
Also: skip git checkout when HEAD already matches target SHA (zero mtime
changes), and drop `-x` from git clean to preserve gitignored files.
Expected: ~3.7min → <1min for unchanged-crate rebuilds on warm PVC.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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