feat(view,tests): query blocks stay code in text the agent did not write

tests/obsidian-stub.ts

@@ -34,6 +34,12 @@ export const moment = () => undefined;
 export const requestUrl = () =>
   Promise.reject(new Error("no network in the stub"));
 export const setIcon = () => undefined;
+export const MarkdownPreviewRenderer = {
+  codeBlockPostProcessors: { tasks: () => undefined } as Record<
+    string,
+    unknown
+  >,
+};
 
 function escapeHtml(value: string): string {
   return value