feat: expose workflow execution modes in editor

backend/app/domains/rendering/workflow_config_utils.py

@@ -171,7 +171,10 @@ def build_preset_workflow_config(
         "version": 1,
         "nodes": nodes,
         "edges": edges,
-        "ui": {"preset": preset_type},
+        "ui": {
+            "preset": preset_type,
+            "execution_mode": "legacy",
+        },
     }
 
 
@@ -214,7 +217,10 @@ def _canonicalize_legacy_custom_config(raw: dict[str, Any]) -> dict[str, Any]:
         "version": 1,
         "nodes": nodes,
         "edges": edges,
-        "ui": {"preset": "custom"},
+        "ui": {
+            "preset": "custom",
+            "execution_mode": "legacy",
+        },
     }
 
 
@@ -225,6 +231,11 @@ def canonicalize_workflow_config(raw: dict[str, Any]) -> dict[str, Any]:
     if "version" in raw and "nodes" in raw:
         normalized = deepcopy(raw)
         normalized.setdefault("edges", [])
+        ui = normalized.get("ui")
+        if not isinstance(ui, dict):
+            ui = {}
+        normalized["ui"] = dict(ui)
+        normalized["ui"].setdefault("execution_mode", "legacy")
         return normalized
 
     workflow_type = raw.get("type")