Add Jellyfin 12.0 release build alongside 10.11

Multi-target the plugin against net9.0 (Jellyfin 10.11.x) and net10.0
(Jellyfin 12.0.x), with per-framework Jellyfin.Controller/Model references.

Jellyfin 12 added a controlling-session parameter to
ISessionManager.ReportCapabilities; an empty value skips the AssertCanControl
check, which is what a server-side registration needs.

Each release now ships two packages, jellylms_<version>_jf11.zip and
jellylms_<version>_jf12.zip, with a manifest entry each. Jellyfin filters by
targetAbi, so both can share a version number. Also corrects the manifest
targetAbi for new releases from 10.10.0.0 to 10.11.0.0 - the plugin has
referenced 10.11 packages since 1.0.0.

jprm only reads ./build.yaml, so build-plugin.sh swaps targetAbi/framework per
variant and restores the file afterwards.

The builder image moves to the .NET 10 SDK, which targets both frameworks.
CA1873 (new in that SDK) is disabled alongside CA1848, same rationale.

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

Jellyfin.Plugin.JellyLMS/Services/LmsDeviceDiscoveryService.cs

@@ -211,7 +211,13 @@ public class LmsDeviceDiscoveryService : IHostedService, IDisposable
             SupportsPersistentIdentifier = true
         };
 
+#if NET10_0_OR_GREATER
+        // Jellyfin 12 added a controlling session parameter; an empty value skips the
+        // "can control" assertion, which is what we want for a server-side registration.
+        sessionManager.ReportCapabilities(string.Empty, session.Id, capabilities);
+#else
         sessionManager.ReportCapabilities(session.Id, capabilities);
+#endif
 
         // Track this device
         _registeredDeviceIds[player.MacAddress] = deviceId;