Unusable-worktree recovery preserved task.worktree whenever the failing path
differed from it, treating the difference as proof the recorded worktree was
live. The reported strand had both gone: an AI-merge clean room refused as an
"incomplete worktree" while the task worktree had already been removed, so
every requeue re-dispatched into a missing directory ("Working directory does
not exist … Cannot execute bash commands") until the retry budget burned out
and the card parked failed in review. Preserve the recorded worktree only when
it is still a usable checkout; otherwise clear it so the next dispatch builds a
fresh one from the branch.
Also splits the planning-stage guard: only the DURABLE replan parks
(needs-replan, plan-review-unavailable) outrank sticky execution stamps.
"planning" is the transient planner claim, so a stamp landing on it still means
execution won the FN-8361 race.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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