Workflow executions list. One LiveView covers two URLs:
/executions— all executions on this instance/workflows/:name— executions filtered to a single workflow
A faceted ExecutionFilters bar (workflow / status / time / id) drives the
URL params; the DataTable LiveComponent renders rows and pagination from
the resulting query. URL params are the single source of truth — both the
filter bar and the table notify us, and we patch the URL in response.