@yao-pkg/pkg's SEA bootstrap extracts native addons from the VFS into a
per-user cache ($PKG_NATIVE_CACHE_PATH/pkg/<sha256>/) with plain
writeFileSync, so concurrent first starts of the same executable truncate
files another process has already mapped: SIGBUS on Linux, "Library not
loaded" for sharp's libvips on macOS. Extend the existing pnpm patch so the
three write sites go through a same-directory temporary file and
renameSync; a cache path is then either absent or complete, every process
finishes its own copy pass before it loads, and identical content makes
concurrent renames harmless without a lock. Cache location, hash keying,
and per-file comparison are unchanged. The single-exe Agent Note records
the decision and the measured before/after runs.
Closes#4664
fz
5992977f2e