Since real device names started reaching the header, an accented one
made login impossible: dart:io refuses header values above 0x7F, and
CFNetwork puts the raw code unit on the wire as a Latin-1 byte, which
Kestrel rejects as a malformed request with 400 before Jellyfin routes
POST /Users/AuthenticateByName.
Encode every field the way the official Jellyfin SDK does; the server
already reverses it with WebUtility.UrlDecode, so the wire value stays
pure ASCII while the device list shows the real name. Quotes, commas
and `=` no longer need stripping either. sanitizeHeaderValue, which
still guards the Plex headers, now folds Latin letters to their base
form instead of emitting bytes no transport accepts.
close#1685
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