Follow-up to 9492ed4c4: when the merge was empty (no commit made),
filesChanged/insertions/deletions were still being captured from
git show --shortstat HEAD — which describes pre-merge HEAD's commit,
unrelated to this task. Consumers (dashboard, audit log) would render
those numbers next to "no commit landed", which is misleading.
Clear stats to 0 alongside the omitted commitSha. Also drop the stats
line from the agent-log summary when mergeWasEmpty.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
964c55da77