Add a 'lint' job to the JS tests workflow that runs 'eslint --fix'
across all discovered npm workspaces (same matrix as the check job).
Fixable issues auto-correct and don't block; eslint exits non-zero
only when un-fixable errors remain.
Also fix duplicate 'needs: workspaces' in the check job.
The set-matrix step wrote the npm workspace query result directly to
$GITHUB_OUTPUT. If discovery ever produced [], the matrix would expand
to zero check jobs, leaving the reusable workflow green without running
any JS/TS checks.
Now the step validates the result is a non-empty array before emitting
it, and exits 1 with a GitHub annotation if it's empty or jq failed.
