`dart format --set-exit-if-changed` over lib and test rewrites these.
The analysis job never reached its formatting step, so the drift went
unnoticed. No behaviour changes.
Resolve platform, hardware model, and friendly device name once via a
shared DeviceIdentityService and send them to both backends: Plex gets
a real X-Plex-Platform plus X-Plex-Device/X-Plex-Device-Name (shown as
Player in dashboards/Tautulli), Jellyfin gets the device name in the
MediaBrowser auth header. Transcode and live-TV decision requests keep
their pinned platform names, which Plex validates server-side.
close#1270
edde746