actions/upload-artifact@v4 and download-artifact@v4 use GitHub's newer
Artifacts-v2 protocol, which Forgejo's server explicitly refuses
("not currently supported on GHES"). Forgejo maintains its own forks
(forgejo/upload-artifact@v5, forgejo/download-artifact@v7) with that
check disabled. Also drops archive: false, an input that fork doesn't
expose - the earlier binary rename already keeps filenames distinct
through the default zip/extract round-trip.
Builds macos-arm64 and linux-x86_64 release binaries in parallel and
uploads them as build artifacts; a single release job gated on both
then downloads and publishes them to one Forgejo release. Splitting it
this way avoids a real race in actions/forgejo-release itself: its
script always does a blind create-then-upload for the tag with no
merge path, so two parallel callers against the same tag either
hard-fail or stomp each other's uploaded assets.
Renamed macos.yml to ci.yml with two jobs (macos, linux) under one
push/PR/dispatch trigger, so both run from the same commit instead of
needing separate files. Cache keys are now OS-prefixed (cargo-macos-/
cargo-linux-): target/ artifacts are platform-specific and would
otherwise collide under a shared key.
