Tracking raw agent-commit count meant an agent that committed only its
inherited baseline WIP (via `git add -A`) then left the real edit
uncommitted collapsed every filtered patch to empty, so tmpDir never
advanced past baselineSha yet the leftover path assumed it had.
replayFilteredAgentCommits now counts filtered commits actually applied
and, when zero landed, bypasses the finalFilteredTree/leftoverPatch
synthesis entirely — writeSyntheticTree(HEAD, [rootPatch]) fails hard
whenever rootPatch has HEAD+WIP context for a file missing from HEAD's
index (untracked / staged-new WIP). Instead, commit rootPatch directly
with WIP seed, matching the no-agent-commit path.
Added regression test covering the reviewer's scenario.
roboomp
ecbf0760cf