style: ruff format after MCP server integration

Reformat the files touched by Tasks 1-14 of the host-agent MCP server
plan. No semantic changes; pre-existing format issues in unrelated
files (test_templates, test_skill_sync_wiring, 0010_skill_management,
test_skill_catalog_mcp) left untouched for a separate housekeeping
pass.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/device-host-agent/tests/test_assignment.py

@@ -154,7 +154,14 @@ def test_workflow_assignment_maps_cancellation_stop_to_cancelled_status() -> Non
             return object() if definition_id == "workflow-a" else None
 
     class FakeWorkflowRunner:
-        def run(self, loaded_definition, device_id: str, *, should_stop=None, stop_reason=None):
+        def run(
+            self,
+            loaded_definition,
+            device_id: str,
+            *,
+            should_stop=None,
+            stop_reason=None,
+        ):
             assert should_stop is not None and should_stop()
             assert stop_reason is not None
             return SimpleNamespace(