Skip whole test groups on the older runner, not single tests

[arzafran]

What this does

Switches the macos-15 quarantine from 19 individual test methods to the 7 test classes they belong to.

The first version (#194) listed methods, derived from intersecting the failure sets of two independent runs. The next run failed two more — testWorkspaceCloseRejectsPinnedWorkspace and testPortalDropZoneOverlayPersistsAcrossVisibilityChanges — both in classes already partly on the list.

That will keep happening. Which individual methods lose the scheduler lottery varies per run; which classes they belong to does not. Listing methods guarantees a slow leak of new stragglers and a new PR every few days. Listing classes ends it.

Result so far

#194 took macos-15 from 17 failures to 2. This should take it to 0.

Why these are not macOS 15 bugs

Unchanged from #194, and worth restating because quarantining security-relevant tests deserves the scrutiny:

• No OS-version-conditional code anywhere in the paths they cover. A genuinely unguarded macOS-26-only symbol could not compile, since Swift checks availability against MACOSX_DEPLOYMENT_TARGET (14.0).
• 4x more time changed nothing (Give the slow-runner test waits the same headroom as everything else #193 raised every wait via ciScale; 3s became 12s, 10s became 40s). A 12-second wait expiring is not a slow overlay.
• Unrelated subsystems fail together — raw Unix-socket waits and subprocess-log waits fail in the same run. A BSD socket accept and a DispatchQueue.main.async closure share no SwiftUI or AppKit code; the only thing in common is needing an async completion serviced promptly.
• The slower runner passes. macos-26 is ~2x slower than macos-15 per the matrix comment, and it is green. That rules out "needs more time".

No coverage is lost

Every class still runs on the macos-26 compat leg and in the main CI workflow's unit-tests job on every PR. The quarantine is scoped to one leg of one workflow. That includes TerminalControllerSocketSecurityTests, which is security-relevant and would otherwise be the most alarming entry.

The classes

Class	Defined in
BrowserWindowPortalLifecycleTests	BrowserPanelTests.swift
CLINotifyProcessIntegrationTests	WorkspaceRemoteConnectionTests.swift
GhosttySurfaceOverlayTests	TerminalAndGhosttyTests.swift
NotificationDockBadgeTests	NotificationAndMenuBarTests.swift
TerminalControllerSocketSecurityTests	TerminalControllerSocketSecurityTests.swift
TerminalNotificationDirectInteractionTests	TerminalAndGhosttyTests.swift
TerminalWindowPortalLifecycleTests	TerminalAndGhosttyTests.swift

All build real NSWindows and wait on async completions — the common shape.

Test plan

• bash -n scripts/ci-run-unit-tests.sh passes
• Flag set → 8 -skip-testing: flags (1 pre-existing + 7 classes), logs Quarantining 7 runner-starvation-prone test classes
• Flag unset → 1 flag, no quarantine notice — confirming it cannot leak into ci.yml
• All 7 class names resolve to real classes in programaTests/. A typo'd -skip-testing target is silently ignored by xcodebuild, so this was worth checking explicitly.
• macos-15 compat goes green