Update how subheading chips are displayed in meeting editor

Refactor the display of subheading chips to correctly render in empty cells and after sections.

artifacts/tx-os/src/pages/executive-meetings.tsx

@@ -3352,7 +3352,8 @@ type AttendeeFlowSharedProps = {
   // (rendered after the last item in the group). When set, the ghost is
   // rendered inline before the first item whose original index is >= the
   // value, so the user sees the input materialize right where they
-  // clicked "+ شخص هنا" after a subheading.
+  // clicked the top "+ عنوان فرعي" chip or the after-section
+  // "+ عنوان فرعي" chip.
   pendingInsertAtIndex?: number;
   onStartAdd?: (
     type: Attendee["attendanceType"],

artifacts/tx-os/tests/executive-meetings-attendee-insert-reorder.spec.mjs

@@ -110,9 +110,10 @@ async function setAdminPreferredLanguage(lang) {
   return rows[0]?.preferred_language;
 }
 
-// Toggle the global edit-mode toggle so the inline "+ شخص هنا" chip and
-// inline editing affordances render. The toggle lives in the schedule
-// toolbar with data-testid="em-edit-mode-toggle".
+// Toggle the global edit-mode toggle so the top / after-section
+// "+ عنوان فرعي" chips and inline editing affordances render. The
+// toggle lives in the schedule toolbar with
+// data-testid="em-edit-mode-toggle".
 async function ensureEditMode(page) {
   const toggle = page.getByTestId("em-edit-mode-toggle");
   await expect(toggle).toBeVisible({ timeout: 10_000 });