License: running server keeps running until the next restart

The configurable LicenseGraceHours setting is gone. If the master is down or
rejects the key, a running server now only warns and keeps running until the
next restart; a (re)start still works up to 72 h after the last confirmation.

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

ConfigEditor.cs

@@ -15,7 +15,6 @@ public static class ConfigEditor
         requireSteam = config.RequireSteam,
         publicAddress = config.PublicAddress,
         saveSyncMinutes = config.SaveSyncMinutes,
-        licenseGraceHours = config.LicenseGraceHours,
         autosaveSeconds = config.AutosaveSeconds,
         port = config.Port,
         panelEnabled = config.PanelEnabled,
@@ -70,7 +69,6 @@ public static class ConfigEditor
         config.PublicAddress = Text("publicAddress", config.PublicAddress, 200);
         config.SaveSyncMinutes = Number("saveSyncMinutes", config.SaveSyncMinutes, 0, 240);
         config.AutosaveSeconds = Number("autosaveSeconds", config.AutosaveSeconds, 10, 3600);
-        config.LicenseGraceHours = Number("licenseGraceHours", config.LicenseGraceHours, 1, 720);
 
         int before = changed.Count;
         int oldPort = config.Port, oldPanelPort = config.PanelPort;