Complete local generalisation tasks and document remaining experiment blockers

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a0e76f-be98-7ae3-965d-e0b31290a4c4

tests/test_agentic_realization.py

@@ -173,3 +173,19 @@ def test_the_control_arm_is_not_a_straw_man():
     preserved = [m for m in MECHANICAL if m.preserves_test_ids]
     assert all(realized_ok(m.id, runtime=runtime) for m in preserved)
     assert len(preserved) >= 9
+
+
+def test_deciding_axis_has_ten_mutations_and_paired_structural_controls():
+    from lab.mutations import EXTENDED_LAYOUTS
+    from lab.http_api import render_resource_page
+    from lab.mutations import build_lab
+    assert sum(not m.preserves_test_ids for m in MECHANICAL) >= 10
+    for dropped, preserved, _, _ in EXTENDED_LAYOUTS:
+        dropped_app, _ = build_lab(dropped)
+        preserved_app, _ = build_lab(preserved)
+        # Version metadata differs; control markup must differ only in test ids.
+        import re
+        def shape(app):
+            html = render_resource_page(app, "alice", "R")
+            return re.sub(r'\s*data-td(?:-version)?="[^"]*"', "", html)
+        assert shape(dropped_app) == shape(preserved_app)