Nothing removed the returned marker, so a spec healed via grill stayed blocked
forever — confirmed live on a real issue. to-spec now clears the marker when it
republishes the rewritten spec to the same source: spec-execution sets, to-spec
clears, one owner per transition (ADR 0008). Marker renamed to a state
(Returned: spec-defect), not a Returns: N counter that was never counted.
Proven end-to-end: set -> refuse -> heal+clear -> release.

version 0.9.1 -> 0.9.2; check + validate --strict green.