Own server tags in the web panel (Settings) and server.json

Tags (max. 6, normalized like the keymaster) are sent with the heartbeat;
official and featured are only given by the MSCO admins and are refused with
a note. MSCO_TAGS environment variable.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Tests/Program.cs

@@ -486,6 +486,17 @@ async Task PanelTests()
     using (var da = new System.IO.Compression.ZipArchive(new MemoryStream(downZip)))
         Check(down.IsSuccessStatusCode && da.GetEntry("defaultES2File.txt") != null, "The current save can be downloaded as ZIP");
 
+    // Eigene Tags: bereinigt, "official"/"featured" nur über die MSCO-Admins
+    var cleanTags = ServerConfig.NormalizeTags(new[] { " Deutsch ", "Role Play!", "OFFICIAL", "für alle", "deutsch", "featured" }, out var reservedTags);
+    Check(string.Join(",", cleanTags) == "deutsch,role-play,fuer-alle" && string.Join(",", reservedTags) == "official,featured",
+          "Tags are normalized and official/featured are reserved: " + string.Join(",", cleanTags));
+    var tagRes = await Call(owner, "POST", "api/config", new { tags = "Vanilla, official, Deutsch" });
+    Check(tagRes.status == 200 && tagRes.json.GetProperty("message").GetString().Contains("only given by the MSCO admins")
+          && string.Join(",", ServerConfig.LoadOrCreate(configPath, out _).Tags) == "vanilla,deutsch",
+          "Own tags can be set in the panel, official is refused: " + tagRes.json);
+    var tagCfg = await Call(owner, "GET", "api/config");
+    Check(tagCfg.json.GetProperty("tags").GetString() == "vanilla, deutsch", "The panel shows the tags");
+
     // Updates: Versionen vergleichen, Status im Panel, Installieren nur mit verfügbarem Update
     Check(Updater.ParseCsprojVersion("<Project><PropertyGroup><Version>2.10.1</Version></PropertyGroup></Project>") == "2.10.1"
           && Updater.ParseModVersion("public const string ModVersion = \"2.9\";") == "2.9", "Update versions are read from the source");