Add test for anchored prototypes (#30526)

Nothing fails at least but at some point will let us remove some hacky engine code.

Content.IntegrationTests/Tests/Physics/AnchorPrototypeTest.cs

@@ -0,0 +1,43 @@
+using Robust.Shared.GameObjects;
+using Robust.Shared.Physics;
+using Robust.Shared.Physics.Components;
+using Robust.Shared.Prototypes;
+
+namespace Content.IntegrationTests.Tests.Physics;
+
+[TestFixture]
+public sealed class AnchorPrototypeTest
+{
+    /// <summary>
+    /// Asserts that entityprototypes marked as anchored are also static physics bodies.
+    /// </summary>
+    [Test]
+    public async Task TestStaticAnchorPrototypes()
+    {
+        await using var pair = await PoolManager.GetServerClient();
+
+        var protoManager = pair.Server.ResolveDependency<IPrototypeManager>();
+
+        await pair.Server.WaitAssertion(() =>
+        {
+            foreach (var ent in protoManager.EnumeratePrototypes<EntityPrototype>())
+            {
+                if (!ent.Components.TryGetComponent("Transform", out var xformComp) ||
+                   !ent.Components.TryGetComponent("Physics", out var physicsComp))
+                {
+                    continue;
+                }
+
+                var xform = (TransformComponent)xformComp;
+                var physics = (PhysicsComponent)physicsComp;
+
+                if (!xform.Anchored)
+                    continue;
+
+                Assert.That(physics.BodyType, Is.EqualTo(BodyType.Static), $"Found entity prototype {ent} marked as anchored but not static for physics.");
+            }
+        });
+
+        await pair.CleanReturnAsync();
+    }
+}