Add planner previews and streaming

tests/test_agent_runner.py

@@ -24,6 +24,32 @@ class DummySkill(ClickthroughSkill):
             ],
         }
 
+    def plan_with_planner(
+        self,
+        grid_id: str,
+        preferred_label: str | None = None,
+        action: str = "click",
+        text: str | None = None,
+        comment: str | None = None,
+    ) -> Dict[str, Any]:
+        cells = ["dummy-grid-1", "dummy-grid-2"]
+        if preferred_label == "target":
+            target = "dummy-grid-2"
+        else:
+            target = cells[len(cells) // 2]
+        plan = {
+            "grid_id": grid_id,
+            "target_cell": target,
+            "action": action,
+            "text": text,
+            "comment": comment,
+        }
+        return {
+            "plan": plan,
+            "result": {"success": True, "detail": "preview"},
+            "descriptor": {"grid_id": grid_id},
+        }
+
     def plan_action(self, plan: ActionPlan) -> Dict[str, Any]:
         self.last_plan = plan
         return {"success": True, "target_cell": plan.target_cell}