perf(executor): recover approved steps on engine restart

When the engine restarts mid-step, an in-progress step may have already
passed plan + code review but not yet been flipped to done by the agent's
next task_update call. Previously, the next executor pass re-entered the
step and replayed both reviews — measured at 5-20 min of pure waste per
restart (observed in FN-2215 Step 1 and FN-2207 Step 6).

recoverApprovedStepsOnResume scans the task log for any in-progress step
whose most recent "code review Step N: APPROVE" entry is newer than its
most recent "Step N → pending" transition, and marks those steps done
before execute() runs. Safely skips steps that were reset after approval
(e.g. by a workflow revision) or only received REVISE verdicts.

Called from both the engine-restart path (resumeOrphaned) and the
unpause path, matching the two places the task log shows as vulnerable
to this race.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -25,6 +25,13 @@ kb.db/
 # Pi
 .pi/
 
+# VS Code Local History (editor auto-saved snapshots)
+.history/
+
+# Ad-hoc task completion notes left by agents after a run; per-session scratch,
+# never meant to be committed.
+.DONE
+
 # Local kb state and backups
 .kb/
 .fusion-backup/