docs: sync Task 13 conftest with the dir-scoped marker fix

docs/superpowers/plans/2026-07-07-wabot-modernization.md

@@ -3261,8 +3261,10 @@ BROWSERS = ["firefox", "chromium"]
 
 
 def pytest_collection_modifyitems(items):
+    integration_dir = Path(__file__).parent
     for item in items:
-        item.add_marker(pytest.mark.integration)
+        if integration_dir in item.path.parents:
+            item.add_marker(pytest.mark.integration)
 
 
 @pytest.fixture(scope="session")
@@ -3285,6 +3287,8 @@ def store(tmp_path):
     return SessionStore(path=tmp_path / "sessions.json")
 ```
 
+Note: the marker must be scoped to the integration dir — an unscoped hook marks the entire test tree and silently deselects the unit suite.
+
 - [ ] **Step 3: Verify collection behaves**
 
 Run: `uv run pytest --collect-only tests/integration`