The WebM carries real alpha (alpha_mode=1) but rendered opaque because the
VideoTexture was forced to SRGBColorSpace and the material assumed
premultiplied alpha, crushing transparent regions to black. Removing the
colorspace override and setting premultipliedAlpha:false keys the black out.
The /api/admin/ghosts endpoint returns raw DB rows (webm_path,
webp_path, image_path as bare filenames), not the public API's
camelCase URL shape. buildGhost now reads those and prefixes /uploads/,
so WebM video renders in the preview instead of falling through to the
procedural wisp.
Camera-background single-ghost preview reusing the hunt's render path
(WebM VP9+alpha VideoTexture -> WebP/GIF -> procedural wisp). Login gate
matches admin; ghost list via JWT-protected /api/admin/ghosts. Dropdown
to pick a ghost, sliders for distance/size, camera toggle.