Add planner previews and streaming

server/grid.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import Dict, List, Tuple, Any
+from typing import Any, Dict, List, Tuple
 import uuid
 
 from .actions import ActionEngine
@@ -62,24 +62,36 @@ class VisionGrid:
             rows=self.rows,
             columns=self.columns,
             cells=[cell.model for cell in self.cells.values()],
-            metadata={
-                "memo": self.memo or "",
-                "width": self.width,
-                "height": self.height,
-            },
+            metadata=self.metadata,
         )
 
+    @property
+    def metadata(self) -> Dict[str, Any]:
+        return {
+            "memo": self.memo or "",
+            "width": self.width,
+            "height": self.height,
+        }
+
     def resolve_cell_center(self, cell_id: str) -> Tuple[int, int]:
         cell = self.cells.get(cell_id)
         if not cell:
             raise KeyError(f"Unknown cell {cell_id}")
         return cell.center
 
+    def preview_action(self, payload: ActionPayload) -> ActionResult:
+        return self._engine.plan(payload)
+
     def apply_action(self, payload: ActionPayload) -> ActionResult:
         result = self._engine.plan(payload)
         self._action_history.append(result.model_dump())
         return result
 
+    def update_screenshot(self, screenshot_base64: str, memo: str | None = None) -> None:
+        self.screenshot = screenshot_base64
+        if memo:
+            self.memo = memo
+
     @property
     def action_history(self) -> List[dict[str, Any]]:
         return list(self._action_history)