test(ha): pin the default gated task key set

tests/Jellyfin.Server.Implementations.Tests/ScheduledTasks/ScanLeaderOptionsTests.cs

@@ -38,6 +38,42 @@ public class ScanLeaderOptionsTests
             $"Gated keys match no scheduled task: {string.Join(", ", unmatched)}. Known keys: {string.Join(", ", registeredKeys.Order(StringComparer.Ordinal))}");
     }
 
+    /// <summary>
+    /// A key dropped from the default set silently un-gates that task on every replica, so the whole
+    /// set is pinned against a hand-maintained expectation rather than read back from the options.
+    /// </summary>
+    [Fact]
+    public void DefaultGatedTaskKeys_Should_BeTheExpectedSet()
+    {
+        string[] expected =
+        {
+            "AudioNormalization",
+            "CleanupUserDataTask",
+            "DownloadLyrics",
+            "DownloadSubtitles",
+            "KeyframeExtraction",
+            "MoveTrickplayImages",
+            "OptimizeDatabaseTask",
+            "PluginUpdates",
+            "RefreshChapterImages",
+            "RefreshGuide",
+            "RefreshInternetChannels",
+            "RefreshLibrary",
+            "RefreshPeople",
+            "RefreshTrickplayImages",
+            "TaskExtractMediaSegments",
+            "TmdbRefreshUpcomingEpisodes"
+        };
+
+        var actual = new ScanLeaderOptions().GatedTaskKeys;
+        var missing = expected.Except(actual, StringComparer.Ordinal).ToList();
+        var unexpected = actual.Except(expected, StringComparer.Ordinal).ToList();
+
+        Assert.True(
+            missing.Count == 0 && unexpected.Count == 0,
+            $"Default gated task keys drifted. Missing: {Describe(missing)}. Unexpected: {Describe(unexpected)}.");
+    }
+
     /// <summary>
     /// The key universe is only as complete as the assemblies it is read from, so a task added to an
     /// unscanned assembly must fail here rather than narrow what the previous test can catch.
@@ -69,6 +105,9 @@ public class ScanLeaderOptionsTests
         Assert.True(missing.Count == 0, $"Assemblies declaring scheduled tasks but not scanned: {string.Join(", ", missing)}");
     }
 
+    private static string Describe(IReadOnlyCollection<string> keys)
+        => keys.Count == 0 ? "none" : string.Join(", ", keys.Order(StringComparer.Ordinal));
+
     private static HashSet<string> DiscoverScheduledTaskKeys(IEnumerable<Assembly> assemblies)
     {
         var keys = new HashSet<string>(StringComparer.Ordinal);