- fixture-integrity: probe media via media-engine probeMedia (resolves the
bundled static ffmpeg) instead of bare system ffprobe, which is ENOENT in CI;
gate on ffmpegAvailable() like the other media tests
- a11y: regenerate a11y-baseline.json to include the mobile device keys (the
baseline only had desktop keys, so the mobile a11y scan saw them as new)
- device-visual: tag @visual and exclude it from the PR mobile-smoke gate
(darwin-only screenshots cannot pass on linux; nightly + update-visual-baselines
still run it to seed linux goldens)