feat: add system tools and state updates

backend/services/workflow_engine.py

@@ -11,6 +11,7 @@ from typing import Any
 
 from services.node_specs import normalize_graph
 from services.runtime_variables import DynamicVariableStore
+from services.system_tools import normalize_system_tools
 
 
 @dataclass(frozen=True)
@@ -24,6 +25,8 @@ class AgentStageConfig:
     vision_enabled: bool
     vision_model_resource_id: str | None
     tool_ids: tuple[str, ...]
+    system_tools: tuple[str, ...]
+    state_variable_names: tuple[str, ...]
     knowledge_base_id: str | None
     knowledge_mode: str
     knowledge_top_n: int
@@ -145,6 +148,16 @@ class WorkflowEngine:
                 str(source.get("visionModelResourceId") or "") or None
             ),
             tool_ids=tuple(str(tool_id) for tool_id in source.get("toolIds") or []),
+            # System tools and their writable state scope always belong to the
+            # Agent node. They are permissions, not inheritable model config.
+            system_tools=normalize_system_tools(data.get("systemTools")),
+            state_variable_names=tuple(
+                dict.fromkeys(
+                    str(name)
+                    for name in data.get("stateVariableNames") or []
+                    if str(name)
+                )
+            ),
             knowledge_base_id=knowledge_base_id or None,
             knowledge_mode=(
                 str(source.get("knowledgeMode") or "automatic")