Layer docker-compose.gpu.yml to mount /dev/dri/{card0,renderD128}
into pp-app, add it to render (992) + video (44) groups, and set
PHOTOPRISM_FFMPEG_ENCODER=vaapi. Hosts without a VA-API device just
skip the overlay (`-f docker-compose.yml -f docker-compose.gpu.yml`
becomes opt-in per deploy).
Drops video transcode + thumbnail generation from CPU to the iGPU
where present — large win for HEVC libraries. README documents the
flag; default behavior on the base compose is unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
