#28430 cmux-next tests: quarantine the multiWindow classic upgrade order check (#28425)

ClassicUpgradeSimulationTests.theFirstLaunchBringsEverythingOnce("multiWindow") fails intermittently on base and on unrelated PRs, most recently #28283's daemon tests. The workspaces show in swapped order at ClassicUpgradeSimulationTests.swift:45 and :52, for example multiWindow: order differs: ["w1 0", "w1 2", "w1 1", "w1 3"] for ["w1 0", "w1 1", "w1 2", "w1 3"].

Tracking: #28425. Cause: the sidebar placements a run queues through PersonalPlacementQueue (#26153) trail it on a loaded runner. A late slot placement undoes the group the run set, and the simulator reads the order before the queue drains. The fix is #28362.

Change

Only that case's verify runs inside withKnownIssue(..., isIntermittent: true), which names #28425. The other seven matrix cases, the other tests and the rest of that case's expectations are unchanged. #28362 removes this quarantine.

No capture: test-only change.

Risk: low. One test case's order and group checks become a known issue until the fix lands.

Agent session: agent session

🤖 Generated with Claude Code

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Summary by cubic

Quarantines the intermittently failing multiWindow case of ClassicUpgradeSimulationTests.theFirstLaunchBringsEverythingOnce as a known issue (#28425) until the fix in #28362 lands.

The test flakes because sidebar placements a run queues trail it on a loaded runner, showing workspaces in swapped order. Only that case's verify runs inside withKnownIssue(..., isIntermittent: true); the other seven matrix cases and all other expectations are unchanged. Test-only change with low risk.