Complete phase 39 school owners with owner-scoped API, menu, and tests.

Drop golden save load tests in favor of incompatible-save behavior; dress legacy people files on reload; fix AppHost isolation for multi-user socket and save cleanup.

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

src/HSchool.Server/Game/SchoolWorker.cs

@@ -982,8 +982,9 @@ internal sealed class SchoolWorker
 
             if (DressGenerator.NeedsDressing(roster, applicants))
             {
-                throw new SchoolContentUnavailableException(
-                    $"School {_id} people have no clothes; the school was left unstarted.");
+                roster = DressGenerator.EnsureRoster(catalog, roster, seed, school.Clock.Time);
+                applicants = DressGenerator.EnsurePool(catalog, applicants, roster, seed, school.Clock.Time);
+                generated = true;
             }
 
             RequireKnownApparel(catalog, roster, applicants);