fix(review): skip ToolbarHost mousemove when unfocused, drop type cast

Address PR review nits on #660:

- ToolbarHost's window mousemove listener now bails on `!isFocused`,
  so dock-mounted-but-hidden panels don't track mouse for a toolbar
  the user can't see. Matches the intent of the existing isFocused
  prop already passed through to the hook for draft handling.

- Widen useAnnotationToolbar's handleMouseMove arg to a structural
  `{clientX, clientY}` shape. The hook only reads those two fields,
  so accepting the structural shape eliminates the
  `as unknown as React.MouseEvent` cast in ToolbarHost while staying
  compatible with React.MouseEvent callers.

Author: backnotprop

packages/review-editor/components/ToolbarHost.tsx

@@ -87,14 +87,13 @@ export const ToolbarHost = forwardRef<ToolbarHostHandle, ToolbarHostProps>(funct
   // Replaces the parent's `onMouseMove={toolbar.handleMouseMove}` on its scroll
   // container — the hook only stashes clientX/Y for toolbar placement, so a
   // window-level listener is functionally equivalent for that purpose.
+  // Skip when not focused so dock-mounted-but-hidden panels don't track.
   const handleMouseMove = toolbar.handleMouseMove;
   useEffect(() => {
-    const onMove = (e: MouseEvent) => {
-      handleMouseMove({ clientX: e.clientX, clientY: e.clientY } as unknown as React.MouseEvent);
-    };
-    window.addEventListener('mousemove', onMove);
-    return () => window.removeEventListener('mousemove', onMove);
-  }, [handleMouseMove]);
+    if (!isFocused) return;
+    window.addEventListener('mousemove', handleMouseMove);
+    return () => window.removeEventListener('mousemove', handleMouseMove);
+  }, [handleMouseMove, isFocused]);
 
   useImperativeHandle(
     ref,

packages/review-editor/hooks/useAnnotationToolbar.ts

@@ -133,8 +133,10 @@ export function useAnnotationToolbar({ patch, filePath, isFocused, onLineSelecti
     setDecorations([]);
   }, []);
 
-  // Track mouse position continuously for toolbar placement
-  const handleMouseMove = useCallback((e: React.MouseEvent) => {
+  // Track mouse position continuously for toolbar placement.
+  // Accepts a structural shape so the same handler works for both React
+  // synthetic events and native DOM MouseEvents (used by ToolbarHost).
+  const handleMouseMove = useCallback((e: { clientX: number; clientY: number }) => {
     lastMousePosition.current = { x: e.clientX, y: e.clientY };
   }, []);