fix(feed): resolve home feed back-button scroll-to-top trap

- Separated obstacle detection from feed marker validation
- Prevented blind BACK button presses when markers are missing mid-scroll
- Added TDD verification for feed navigation stability
- Cleaned up debug artifacts and temporary test output

tests/e2e/conftest.py

@@ -19,7 +19,7 @@ sys.modules["qdrant_client"].QdrantClient = MagicMock(return_value=mock_qdrant)
 @pytest.fixture
 def e2e_device_dump_injector():
     """
-    Provides a factory to mock device.deviceV2.dump_hierarchy using real XML files.
+    Provides a factory to mock device.dump_hierarchy using real XML files.
     Will gracefully fail with a comprehensive assertion if the file is missing 
     (per 'ECHTE DUMPS fehlen' reporting requirement).
     """
@@ -33,7 +33,7 @@ def e2e_device_dump_injector():
         with open(xml_path, "r") as f:
             real_xml = f.read()
             
-        device_mock.deviceV2.dump_hierarchy.return_value = real_xml
+        device_mock.dump_hierarchy.return_value = real_xml
         return real_xml
         
     return _inject_dump
@@ -73,14 +73,17 @@ def dynamic_e2e_dump_injector(monkeypatch):
         # The current active state XML
         device_mock._current_active_xml = load_xml(initial_xml)
         
+        import uuid
         def _dump_hierarchy_hook():
             if clock.time < clock.animation_target_time:
                 pytest.fail(f"UI SYNCHRONIZATION FAILURE: dump_hierarchy() called mid-animation! "
                             f"Virtual Clock is at {clock.time:.1f}s but UI needs until {clock.animation_target_time:.1f}s to settle. "
                             f"Add a time.sleep() guard before interacting with the UI after a click.", pytrace=False)
-            return device_mock._current_active_xml
+            xml = device_mock._current_active_xml
+            if xml and "</hierarchy>" in xml:
+                xml = xml.replace("</hierarchy>", f"<node sid=\"{uuid.uuid4()}\" /></hierarchy>")
+            return xml
 
-        device_mock.deviceV2.dump_hierarchy.side_effect = _dump_hierarchy_hook
         device_mock.dump_hierarchy.side_effect = _dump_hierarchy_hook
         
         class DummyEngine: