v1.58.16

[1.58.16] — 2026-05-20

fix(ui): brand-button hover-flicker — pink/red primary & danger buttons no longer flash on hover (user-reported). Root cause in public/css/app.css: the default .btn-primary / .btn-danger background was a linear-gradient(135deg, var(--rausch) 0%, var(--rausch-dark) 100%); the :hover rule replaced it with a solid var(--rausch-dark). CSS cannot interpolate between a gradient and a solid colour, so the 180 ms transition: background on .btn snapped — the gradient briefly resolved to one of its stops on hover entry/exit, producing the visible white/pink flicker the user reported. Fix: keep the gradient on hover and dim via filter: brightness(0.92) instead — filter interpolates cleanly in every browser, so the dim/un-dim now animates symmetrically over the existing 180 ms duration. The .btn transition list is extended with filter var(--transition) so the hover dim actually animates. Mouse pointer-focus state stays clean (uses :focus, not :focus-visible, per the v1.58.9 M-1 contract). 911 → 912 unit (tests/qa-report-fixes.test.mjs asserts the gradient-stays/filter-dims contract on both .btn-primary:hover and .btn-danger:hover, plus that the pre-fix background: var(--rausch-dark) is gone and that filter is in the .btn transition list). (user-reported)

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