#22598 test(cmux-next): sidebar cards assert the shared card glass veil (base red)

SidebarCardSurfaceTests.theUpdateReadyCardSitsOnTheComposersSurface is red on feat-cmux-next (fleet tip check on 936bad8adcc6, step 42a180113a99a967bff08749): alpha off by 0.09 at :52 and RGB mismatch at :54.

Cause: 17228e100b16 ("restart cmux-tui to use new features, and one shared neutral glass for toasts, dialogs and cards", @lawrencecchen) intentionally moved CardSurfaceView from the composer's 13% text fill to the neutral gray veil of FloatingGlassStyle.card (user 2026-10-20, after Rex). On the purple dark theme the card now draws 0.22 alpha gray, the test still expected 0.13 theme text. The new design already has its own test (FloatingGlassStyleTests.theSidebarCardDrawsTheNeutralVeilAndRim). Neither #22566 nor #22488 caused it.

Fix: test only. Both sidebar card tests now expect CardSurfaceView.style.look(isDark:).veil for the card's appearance, with the same 0.01 tolerance, so the Update Ready and notice cards are still checked to share one surface. Renamed to ...SitsOnTheSharedCardSurface. No source change.

@lawrencecchen: this follows your 17228e100b16 design; shout if the cards were meant to keep the composer fill.

Verification (fleet, package-test-lane.sh suite Packages/macOS/CmuxNext CmuxNextAppTests):

• before, on 91f5909f09bb: step cd3f4997c9fe3a8136a2e071
• after, on this branch: step c6ae74727c17f4af181d304d

Changelog

none

🤖 Generated with Claude Code

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Summary by cubic

Fixes the failing SidebarCardSurfaceTests after the card surface moved from the composer's 13% text fill to the shared neutral gray veil of FloatingGlassStyle.card.

• Updates both sidebar card tests to assert CardSurfaceView.style.look(isDark:).veil as the card's appearance, with the same 0.01 tolerance.
• Renames the tests to ...SitsOnTheSharedCardSurface to match the new design.
• No source code changes.