feat: Implement "everyone owns all avatar items" toggle; update server settings, controller logic, and admin UI

DorkNet.Server/Startup/DatabaseBootstrap.cs

@@ -496,6 +496,8 @@ public static class DatabaseBootstrap
                 @"ALTER TABLE ""ServerSettings"" ADD COLUMN IF NOT EXISTS ""ProfanityFilterDisabled"" boolean NOT NULL DEFAULT false;");
             await db.Database.ExecuteSqlRawAsync(
                 @"ALTER TABLE ""ServerSettings"" ADD COLUMN IF NOT EXISTS ""CharadesSlotBindingsJson"" text NOT NULL DEFAULT '';");
+            await db.Database.ExecuteSqlRawAsync(
+                @"ALTER TABLE ""ServerSettings"" ADD COLUMN IF NOT EXISTS ""AllAvatarItemsOwned"" boolean NOT NULL DEFAULT false;");
             return;
         }
 
@@ -570,6 +572,18 @@ public static class DatabaseBootstrap
             // ignore the duplicate-column error; any other schema problem
             // will surface when EF reads ServerSettings.
         }
+
+        try
+        {
+            await db.Database.ExecuteSqlRawAsync(
+                @"ALTER TABLE ""ServerSettings"" ADD COLUMN ""AllAvatarItemsOwned"" INTEGER NOT NULL DEFAULT 0;");
+        }
+        catch
+        {
+            // SQLite has no ADD COLUMN IF NOT EXISTS. If it already exists,
+            // ignore the duplicate-column error; any other schema problem
+            // will surface when EF reads ServerSettings.
+        }
     }
 
     private static async Task EnsureInventorySchemaAsync(DorkNetDbContext db)