DOM-free SlideshowController (discrete nav, fragment holds, branch stack)
driving the existing player; <hyperframes-slideshow> web component with a
unified mute+nav capsule (conditional prev/next), floating hotspot overlays,
presenter mode (BroadcastChannel), keyboard/touch, and a scenes getter fed
via the runtime message handler.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The render pre-flight check shells out to `which ffmpeg`, which only
searches the server process's PATH. When Studio is launched from a
GUI/Dock/launchd context that PATH lacks /opt/homebrew/bin, so `which`
fails even when ffmpeg is installed — and POST /render returns 503
"FFmpeg not found".
Fall back to probing well-known install dirs (Homebrew on Apple Silicon
and Intel, plus system/Linux locations) when the PATH lookup fails.
Also drop the [kf:static]/[kf:runtime] keyframe diagnostics that were
spamming the Studio console in prod, and fix two unrelated CI breakages
the branch inherited: a Windows-sensitive ffmpeg test (pin platform) and
a stale player test mock missing onRuntimeReady.
width/height attributes went through parseInt with no validation, so a
typo like width="abc" reached scaleIframeToFit as NaN (invalid
scale(NaN) transform) and width="0" as a division by zero — both
blank the player with no signal. The stage-size message check had the
sibling gap: `> 0` alone lets Infinity through, which scales the
iframe to 0.
Reuse the composition probe's readPositiveDimension guard for the
attribute path (the probe path already rejected these) and add the
same finite-check the adjacent timeline branch uses for stage-size.
Mirrors the clampPlaybackRate hardening from #1120.
Co-authored-by: Carlos Alcaraz <193642530+calcarazgre646@users.noreply.github.com>
James Russo