`remove(slot, false)` dropped the slot without `terminate()`, leaving the OS thread and its heap alive — invisible to RSS, which is why 55 orphaned `MessagePort`s took 16 h to surface. Removing the parameter rather than keeping it is the correct call: the pool was its only owner.
---
Validated in one consolidated worktree cut from `release/v3.8.51`, boarded together with the other 13 PRs of this batch — zero merge conflicts between them.
- `typecheck:core` clean
- complexity 2799 / baseline 3218 and cognitive-complexity 1265 / baseline 1437 — both under baseline
- 71 focused assertions green across the 13 test files this batch adds or touches
⚠️ base-red inherited: #12732 — `Docs Gates (fast-path)`, `Merge integrity`, `No new ESLint warnings`, `Unit Tests fast-path` and `Fast Quality Gates` all reproduce on the pure `release/v3.8.51` tip (provider count 356 vs the 358 the modules define, SKILL.md drift, and `open-sse/utils/stream.ts` at 3115 > frozen 3098). None of them touch this diff.
Thanks @anhtahaylove — the root-cause write-up, the measured before/after numbers and the red-before-green proof on every one of these made the batch reviewable as a unit.
85a5126dba