fix(shared): keep block markers after a task checkbox as visible text

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/shared/src/document-anchors.test.ts

@@ -99,6 +99,8 @@ describe("document text projection", () => {
   it("keeps text the renderer shows literally", () => {
     expect(projectMarkdownToText("# - Roadmap").text).toBe("- Roadmap");
     expect(projectMarkdownToText("> # - Quoted heading").text).toBe("- Quoted heading");
+    expect(projectMarkdownToText("- [ ] # Release").text).toBe("# Release");
+    expect(projectMarkdownToText("- [x] - Shipped").text).toBe("- Shipped");
     expect(projectMarkdownToText("Intro\n\n| --- |").text).toBe("Intro ---");
     expect(projectMarkdownToText("| A | B |\n| --- | --- |\n| 1 | 2 |").text).not.toContain("---");
     expect(projectMarkdownToText("Show \\& and &Amp; and &constructor;").text)

packages/shared/src/document-anchors.ts

@@ -275,9 +275,11 @@ function stripBlockSyntax(line: string, absoluteOffset: number): { text: string;
       consumed += quote[0].length;
       continue;
     }
-    const listItem = rest.match(/^\s*(?:[-+*]|\d+[.)])\s+(?:\[[ xX]\]\s+)?/);
+    const listItem = rest.match(/^\s*(?:[-+*]|\d+[.)])\s+(\[[ xX]\]\s+)?/);
     if (listItem) {
       consumed += listItem[0].length;
+      // A task checkbox starts the item's paragraph, so markers after it stay visible.
+      if (listItem[1]) break;
       continue;
     }
     // Heading text is inline content, so markers after `#` stay visible.