Shard 2 ran all 132 files with zero (fail) lines yet bun exited 1 —
unhandled errors in a shape neither counter names, and the Windows
lane had no log artifact to attribute them. Statically attributed and
excluded: browser-skill-commands (spawnSkill spawns bun with a
constructed env; resolution fails under Windows spawn) and
security-audit-r2 (evil-link symlink fixtures need Developer Mode).
The lane now uploads its shard logs on failure like free-tests.yml,
with os.tmpdir() pointed at runner.temp so the glob can find them.