fix: validate task tool result details

src/ui.ts

@@ -153,6 +153,16 @@ function renderTaskDetails(tasks: Task[], theme: Theme, width: number): string[]
   return lines;
 }
 
+function isValidTaskToolDetails(details: unknown): details is TaskToolDetails {
+  if (!details || typeof details !== "object") return false;
+  const d = details as Partial<TaskToolDetails>;
+  return (
+    typeof d.action === "string" &&
+    Array.isArray(d.snapshot?.tasks) &&
+    Array.isArray(d.affected)
+  );
+}
+
 export function renderToolResult(
   result: { content: Array<{ type: string; text?: string }>; details?: unknown; isError?: boolean },
   expanded: boolean,
@@ -161,7 +171,7 @@ export function renderToolResult(
   const raw = firstText(result.content);
   const details = result.details as TaskToolDetails | undefined;
 
-  if (result.isError || !details) {
+  if (result.isError || !isValidTaskToolDetails(details)) {
     const rawLines = raw.split("\n").filter(Boolean);
     return new TaskResultComponent((width) => {
       const lines = expanded ? rawLines : rawLines.slice(0, 1);