## Summary
- preserve the gridlock notification wall-clock cooldown across
transient detector clears
- add a regression test for clear-then-rediscover behavior during the
cooldown
- document the cooldown contract and add a patch changeset
## Test plan
- `corepack pnpm --filter @fusion/engine exec vitest run
src/__tests__/notifier.test.ts --project=engine-default
--reporter=verbose -t 'suppresses the same gridlock after a transient
resolution during cooldown'`
- `corepack pnpm --filter @fusion/engine typecheck`
- `corepack pnpm build`
- `corepack pnpm changeset status --output
/tmp/fusion-gridlock-changeset-status.json`
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
- **Bug Fixes**
- Gridlock notifications now remain suppressed during the 15-minute
cooldown, even if the condition temporarily clears and reappears.
- Prevents repeated notifications caused by transient detector-state
changes.
- **Documentation**
- Updated gridlock notification behavior documentation to reflect the
persistent cooldown.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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