fix(ocap-kernel): sort GC krefs before hardening them

[sirtimid]

processGCActionSet sorted the kref list after filterActionsForProcessing had hardened it. Array.prototype.sort writes every element back even when the array is already in order, so any endpoint with two pending GC actions of one type threw a TypeError out of the run loop. One vat dropping two exports in a crank was enough, and it reproduces on main.

Re-landed from #1022 as part of the split of #1021–#1023 into single-defect PRs.

Changes

• filterActionsForProcessing sorts krefs before the harden; the sort in processGCActionSet is gone.
• New test: groups two actions of one type for one vat into a single item.
• Changelog entry for @metamask/ocap-kernel.

Testing

The new test fails on main with TypeError: Cannot assign to read only property '0' and passes with the fix. The full @metamask/ocap-kernel unit suite passes locally.

🤖 Generated with Claude Code

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Note

Low Risk
Small, localized GC ordering fix with a targeted regression test; avoids mutating hardened arrays without changing GC semantics beyond stable kref ordering.

Overview
Fixes a run-loop crash when one endpoint has two or more pending GC actions of the same type (e.g. a vat dropping two exports in one crank).

filterActionsForProcessing now sorts krefs before harden, because sorting a frozen array throws. The duplicate sort in processGCActionSet is removed; the returned queue item still hardens a copy of the sorted list (krefs: [...krefs]).

Adds a regression test that groups two dropExport actions for one vat into a single dropExports item, and documents the fix in the package changelog.

^{Reviewed by Cursor Bugbot for commit 1355e60. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	73.05% ⬆️ +0.01%	9790 / 13401
🔵	Statements	72.9% ⬆️ +0.01%	9954 / 13653
🔵	Functions	73.6% 🟰 ±0%	2301 / 3126
🔵	Branches	67.29% ⬆️ +0.04%	4024 / 5980

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
packages/ocap-kernel/src/garbage-collection/garbage-collection.ts	98.27% 🟰 ±0%	96.66% ⬆️ +3.33%	100% 🟰 ±0%	98.27% 🟰 ±0%	78

Generated in workflow #4850 for commit 1355e60 by the Vitest Coverage Report Action

[FUDCo]

Small is beautiful.