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/host_agent/mcp_token.py

@@ -74,9 +74,7 @@ class McpTokenStore:
                 created_at=datetime.fromisoformat(str(data["created_at"])),
             )
         except (KeyError, TypeError, ValueError) as exc:
-            raise McpTokenStoreError(
-                f"MCP token file schema invalid: {exc}"
-            ) from exc
+            raise McpTokenStoreError(f"MCP token file schema invalid: {exc}") from exc
 
     def _generate_and_write(self) -> McpToken:
         token = McpToken(