fix: align market selection checkboxes

tests/market-dom-sync.test.ts

@@ -307,6 +307,28 @@ describe("market-dom-sync", () => {
     expect(readAuthorNames()).toEqual(["达人 A", "达人 B"]);
   });
 
+  test("inserts the selection column before the native author column", () => {
+    document.body.innerHTML = buildRealMarketGridFixture();
+
+    const table = syncMarketTable(document);
+    if (!table) {
+      throw new Error("Expected market table");
+    }
+
+    expect(readAuthorSectionColumnKeys()).toEqual(["selection", "author"]);
+  });
+
+  test("keeps the selection cells aligned to the native author row heights", () => {
+    document.body.innerHTML = buildRealMarketGridFixture();
+
+    const table = syncMarketTable(document);
+    if (!table) {
+      throw new Error("Expected market table");
+    }
+
+    expect(readSelectionCellHeights()).toEqual(["120px", "120px"]);
+  });
+
   test("uses native-like alignment styles for plugin cells", () => {
     document.body.innerHTML = buildRealMarketGridFixtureWithScopedAttributes();
 
@@ -962,14 +984,37 @@ function readSelectionRowCheckboxCount() {
 }
 
 function readAuthorNames() {
-  const authorColumn = document.querySelector(
-    '[data-testid="author-section"] .content-column'
-  );
+  const authorColumn = Array.from(
+    document.querySelectorAll('[data-testid="author-section"] > .content-column')
+  ).find((column) => (column as HTMLElement).querySelector("a")) as Element | null;
   return readVisualCells(authorColumn).map(
     (cell) => cell.querySelector("a")?.textContent?.trim() ?? ""
   );
 }
 
+function readAuthorSectionColumnKeys() {
+  return Array.from(
+    document.querySelectorAll('[data-testid="author-section"] > .content-column'),
+    (column) => {
+      const element = column as HTMLElement;
+      if (element.dataset.marketColumnGroup) {
+        return element.dataset.marketColumnGroup;
+      }
+
+      return element.querySelector("a") ? "author" : "unknown";
+    }
+  );
+}
+
+function readSelectionCellHeights() {
+  return Array.from(
+    document.querySelectorAll(
+      '[data-testid="author-section"] [data-market-column-group="selection"] > .content-cell'
+    ),
+    (cell) => (cell as HTMLElement).style.height
+  );
+}
+
 function readAuthorRowHiddenStates() {
   return Array.from(
     document.querySelectorAll('[data-testid^="author-cell-"]'),