Every shard + the curated-guard job paid ~71s rebuilding 8 packages' dist
from scratch. actions/cache now restores dist on exact content-hash match
(--print-source-hash; branch-switch stable, pure git-based), with a
--seed-artifact-cache step on cache-hit that defeats the mtime trap
(restored dist looks older than checkout-time src mtimes). No restore-keys
partial fallback: stale dist is a known failure mode here. node_modules is
never cached (Windows junction policy). ensure-test-artifacts still runs as
the authority and rebuilds anything genuinely missing or changed.
39cc659c71