Why: review blockers B1/M2 - Suspend inherited the previous action's
accumulated slots into a new action, and applyCancel swallowed store
errors so an abandoned fill could become an unconfirmed real cancel.
Evidence: review-a1-run.json findings fixed; intentsession/server
tests pass with the reviewer's sequences (verify-a1fix.json).
Impact: different-action suspend starts fresh; non-stale cancel store
errors fail closed; all other flows unchanged.
Refs: feature/intent-multi-turn-a1