feat: consume governed datasources and shared graphs

src/govoplan_dataflow/backend/executor.py

@@ -137,7 +137,7 @@ def execute_preview(
             elif node.type == "source.reference":
                 if source_resolver is None:
                     raise PipelineExecutionError(
-                        "Connector-backed preview requires the Connectors tabular-source capability.",
+                        "Datasource-backed preview requires the Datasources catalogue capability.",
                         node_id=node.id,
                     )
                 resolved = source_resolver(node, MAX_SOURCE_ROWS)
@@ -148,7 +148,7 @@ def execute_preview(
                         "node_id": node.id,
                         "source_ref": resolved.source_ref,
                         "source_name": node.config.get("source_name"),
-                        "kind": "connector",
+                        "kind": "datasource",
                         "provider": resolved.provider,
                         "fingerprint": resolved.fingerprint,
                         "row_count": resolved.total_rows,