**Problem:** Scheduler was re-reading each task's
`task_workflow_selection` once per park-resolution (sweep, hold-release,
moved, unpause/wake), causing a nonstop PostgreSQL query storm (~232
idx_scan/s) on idle polling — a major engine CPU hot-spot.
**Fix:** Memoize the workflow selection per scheduler tick/event —
thread a shared, per-event selection cache through
`resolveWorkflowIrForTask` and all park-resolution handlers, then throw
it away. Each task resolves its parked columns with at most one read of
`task_workflow_selection` per tick. A selection write is always observed
on the next event's fresh cache (never a global/infinite LRU).
**Includes:** regression test asserting the once-per-tick read
invariant, performance changeset + per-tick-cache solution doc,
deploy+verify handoff script, and the parallel quarantine-ledger merge
(origin FN-9125 + RUFU-072 OOM entries both retained).
<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit
* **Performance Improvements**
* Reduced repeated workflow-selection reads during scheduler ticks and
related event processing.
* Improved scheduler and health API responsiveness through per-operation
caching and read deduplication.
* Preserved existing behavior, including retry handling for failed reads
and synchronous data-store support.
* **Documentation**
* Added architectural guidance covering workflow-selection performance,
caching behavior, and verification criteria.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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Co-authored-by: Fusion <noreply@runfusion.ai>
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