New shared component src/ui/preview.js (appFrameUrl + previewLink): song + seed + frame + venue/venueSel deep-links. App honors ?frame= (warm seek on bank-song load) and ?venueSel= via shared pinVenueShell helper (src/venues/pin.js), which filmstrip and venue-gallery now also use. Filmstrip figures and venue-gallery cards wrap canvases; gallery cells stay unlinked (isolated scene probes, not reproducible in-app).
