Port to Jellyfin 12.0 (net10.0, targetAbi 12.0.0.0)

- csproj: net9.0 -> net10.0, version 2.1.0.0 -> 3.0.0.0
- Jellyfin.Controller 10.*-* -> 12.*-* with ExcludeAssets="runtime"
- drop redundant Microsoft.Extensions.Http ref (NU1510 under the .NET 10 SDK;
  IHttpClientFactory comes from the Microsoft.AspNetCore.App framework ref)
- NetAnalyzers 9.0.0 -> 10.0.100
- Endpoints: bare [Authorize] -> [Authorize(Policy = "DefaultAuthorization")]
  now that legacy authorization is disabled by default
- drop unused using in AnilistApi.cs
- build.yaml + manifest.json: 3.0.0.0 / abi 12.0.0.0 entry
- gitignore local dist/ release-artifact dir

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

manifest.json

@@ -7,6 +7,14 @@
         "owner": "ARufenach, modified by Fallenbagel, YannikMG",
         "category": "General",
         "versions": [
+            {
+                "version": "3.0.0.0",
+                "changelog": "Ported to Jellyfin 12.0 (net10.0, targetAbi 12.0.0.0). Plugin API controller now uses the DefaultAuthorization policy instead of a bare [Authorize].",
+                "targetAbi": "12.0.0.0",
+                "sourceUrl": "https://git.umarumg.de/UmaruMG/AnilistSync/releases/download/v3.0.0.0/AnilistSync_3.0.0.0.zip",
+                "checksum": "0d9e73866422ff38a5e2bf305076f728",
+                "timestamp": "2026-09-10T08:54:12Z"
+            },
             {
                 "version": "2.1.0.0",
                 "changelog": "Ported to Jellyfin 10.11 (net9.0, IHostedService). Fixed a broken authorization policy that 500'd every plugin API call. Verified live against 10.11.11 with a real scrobble.",