Tests: null-safe role filter in the gear invariant; scratch roleless design drops its role-naming behaviors

The first full Yggdrasil run at 446c1325 failed these two tests (a design with null Roles; the store refusing Radiator's behaviors once its roles were cleared). Builds: yes.

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

tests/Aetheria.Shared.Tests/ProductLinesCatalogTests.cs

@@ -58,7 +58,7 @@ public sealed class ProductLinesCatalogTests
     {
         using var cache = RestoredHullsTests.OpenCatalog();
         var products = cache.GetAll<FactionProductData>().ToArray();
-        var gear = cache.GetAll<GearData>().Where(d => d is not WeaponItemData && d.Roles.Count > 0).ToArray();
+        var gear = cache.GetAll<GearData>().Where(d => d is not WeaponItemData && (d.Roles?.Count ?? 0) > 0).ToArray();
         Assert.All(OneMakerGear, name => Assert.Contains(gear, d => d.Name == name));
         var sold = 0;
         foreach (var design in gear.Where(d => !OneMakerGear.Contains(d.Name)))

tests/Aetheria.Shared.Tests/ProductLinesCommandTests.cs

@@ -283,6 +283,7 @@ public sealed class GearLineCommandTests : ProductLinesCommandTests
         using (var cache = Open())
         {
             var radiator = cache.GetAll<GearData>().Single(g => g.Name == "Radiator");
+            radiator.Behaviors.Clear(); // the store refuses a behavior that names a role the design lacks
             radiator.Roles.Clear();
             cache.Upsert(radiator);
             cache.FlushAsync().Wait();