feat: checkpoint device agent runtime milestones

runtime/context.py

@@ -7,6 +7,7 @@ from core.models import Scene
 
 if TYPE_CHECKING:
     from runtime.executor import StepResult
+    from world.models import WorldState
 
 
 @dataclass
@@ -15,6 +16,7 @@ class TaskContext:
     goal: str
     scenes: list[Scene] = field(default_factory=list)
     step_results: list["StepResult"] = field(default_factory=list)
+    world: "WorldState | None" = None
 
     def add_scene(self, scene: Scene) -> None:
         self.scenes.append(scene)
@@ -27,4 +29,3 @@ class TaskContext:
         if not self.scenes:
             return None
         return self.scenes[-1]
-