Skip users.json when loading school saves.

The session user list sits beside {id}.json; LoadAll treated it as a school with id 0.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/HSchool.Server/Game/SchoolStore.cs

@@ -119,6 +119,7 @@ internal sealed class SchoolStore
         {
             var fileName = Path.GetFileName(path);
             if (string.Equals(fileName, IndexFileName, StringComparison.OrdinalIgnoreCase)
+                || string.Equals(fileName, UserStore.FileName, StringComparison.OrdinalIgnoreCase)
                 || fileName.EndsWith(".people.json", StringComparison.OrdinalIgnoreCase)
                 || fileName.EndsWith(".timetable.json", StringComparison.OrdinalIgnoreCase))
             {

src/HSchool.Server/Game/UserStore.cs

@@ -8,7 +8,7 @@ internal sealed record UserRecord(string Name);
 /// <summary>Persistent user list beside school saves.</summary>
 internal sealed class UserStore
 {
-    private const string UsersFileName = "users.json";
+    internal const string FileName = "users.json";
 
     private static readonly JsonSerializerOptions Json = new()
     {
@@ -25,7 +25,7 @@ internal sealed class UserStore
     public UserStore(SchoolStore schools, ILogger<UserStore> logger)
     {
         _logger = logger;
-        _path = Path.Combine(schools.DirectoryPath, UsersFileName);
+        _path = Path.Combine(schools.DirectoryPath, FileName);
         Load();
     }