Resolve migration routine loggers from the application container

Jellyfin.Server/ServerSetupApp/StartupLogger.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Globalization;
+using System.Threading;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 
@@ -8,6 +9,8 @@ namespace Jellyfin.Server.ServerSetupApp;
 /// <inheritdoc/>
 public class StartupLogger : IStartupLogger
 {
+    private static readonly AsyncLocal<StartupLogTopic?> _ambientTopic = new();
+
     private readonly StartupLogTopic? _topic;
 
     /// <summary>
@@ -17,6 +20,7 @@ public class StartupLogger : IStartupLogger
     public StartupLogger(ILogger logger)
     {
         BaseLogger = logger;
+        _topic = _ambientTopic.Value;
     }
 
     /// <summary>
@@ -39,6 +43,18 @@ public class StartupLogger : IStartupLogger
     /// </summary>
     protected ILogger BaseLogger { get; set; }
 
+    /// <summary>
+    /// Makes <paramref name="topic"/> the topic that loggers created on this execution context attach to.
+    /// </summary>
+    /// <param name="topic">The topic to nest newly created loggers under.</param>
+    /// <returns>A scope that restores the previously ambient topic when disposed.</returns>
+    internal static IDisposable BeginAmbientTopic(StartupLogTopic? topic)
+    {
+        var scope = new AmbientTopicScope(_ambientTopic.Value);
+        _ambientTopic.Value = topic;
+        return scope;
+    }
+
     /// <inheritdoc/>
     public IStartupLogger BeginGroup(FormattableString logEntry)
     {
@@ -121,4 +137,19 @@ public class StartupLogger : IStartupLogger
             Topic.Children.Add(startupEntry);
         }
     }
+
+    private sealed class AmbientTopicScope : IDisposable
+    {
+        private readonly StartupLogTopic? _previous;
+
+        public AmbientTopicScope(StartupLogTopic? previous)
+        {
+            _previous = previous;
+        }
+
+        public void Dispose()
+        {
+            _ambientTopic.Value = _previous;
+        }
+    }
 }