fix(auth): use the authentication spellings Jellyfin 12.0 leaves enabled

X-Emby-Authorization at the remaining request builders, and api_key= in the
player-facing URLs, become Authorization and ApiKey.

Jellyfin 12.0 disables X-Emby-Authorization, X-Emby-Token, X-MediaBrowser-Token,
the Emby scheme and the api_key query parameter by default — and a migration
(DisableLegacyAuthorization) turns them off on servers upgraded from 10.11 as
well, so this is not confined to fresh installs. A client using them stops
working against an upgraded server rather than degrading.

Verified at source level rather than inferred: AuthorizationContext.cs is
byte-identical between v10.11.5 and v12.0 apart from whitespace. The only change
is the default of the gate that guards the legacy spellings. Authorization with
the MediaBrowser scheme, and ApiKey as a query parameter, are ungated in both
trees — and the server itself emits ApiKey in both (StreamInfo.cs). So one
spelling is correct everywhere and no capability flag is involved.

Also adds ServerCompatibility to ServerInfo: an opaque verdict the frontend
renders without ever comparing a version number, with three states rather than a
boolean. A server newer than this build is usable, not refused; an unreadable
version string is not grounds for refusal either. Only a server below the floor
is refused.

TRACES: UR-085 | DR-286, DR-287

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src-tauri/src/player/mod.rs

@@ -4475,7 +4475,7 @@ mod tests {
             duration: Some(runtime_seconds),
             source: MediaSource::Remote {
                 stream_url:
-                    "http://s/Audio/ep2/universal?api_key=k&AudioStreamIndex=2&StartTimeTicks=0"
+                    "http://s/Audio/ep2/universal?ApiKey=k&AudioStreamIndex=2&StartTimeTicks=0"
                         .to_string(),
                 jellyfin_item_id: "ep2".to_string(),
             },