Complete M11 Creator Studio and M12 Trust & Safety for PC5

- Creator Studio: Visual behavior & property inspector, GLB model importer, binary persistence
- Trust & Safety: 18+ TOS confirmation (DOB removed), creator guidelines & briefing card on join, in-game reporting HUD
- Test Harness: Add --filter, --skip-backend, --skip-godot to run_checkpoint_tests.py

backend/tests/test_auth_age_gate.py

@@ -40,9 +40,10 @@ class TestRegisterRequestDob:
                               date_of_birth="1990-01-01")
         assert req.date_of_birth == date(1990, 1, 1)
 
-    def test_dob_required(self):
-        with pytest.raises(Exception):
-            RegisterRequest(username="u", email="u@example.com", password="p")
+    def test_dob_optional_with_over_18_default(self):
+        req = RegisterRequest(username="u", email="u@example.com", password="p")
+        assert req.date_of_birth is None
+        assert req.over_18 is True
 
     def test_bad_dob_string_rejected(self):
         with pytest.raises(Exception):
@@ -50,6 +51,7 @@ class TestRegisterRequestDob:
                             date_of_birth="not-a-date")
 
 
+
 class TestRegisterAgeGate:
     """End-to-end: the /register endpoint computes age from the DOB."""