The pod already requests gpu.intel.com/i915 and joins the render/video
groups, but Jellyfin transcodes in software until hardware acceleration
is turned on in its encoding config, which the fork does not template.
Seed /config/config/encoding.xml from the init container so VAAPI on the
injected Intel render node (/dev/dri/renderD128) is active on first boot:
HardwareAccelerationType vaapi, EnableHardwareEncoding, h264/hevc decode,
tonemapping left off. Rename the init container to inject-config and write
each seed file only when absent, so admin changes persisted to the shared
RWX /config are never clobbered on restart.
Ben Vincent
ceb2114467