Remove repeated "+ شخص هنا" chip from attendee cells

The Executive Meetings schedule used to render a small dashed "+ شخص هنا"
("+ person here") chip in the gap between every two consecutive person
rows of an attendee cell. With three attendees the user saw three chips
stacked under the names, which looked noisy and repetitive. The user
asked for the chip to be removed entirely; the existing trailing "+"
button at the end of the cell already covers the add-person flow.

Changes:
- artifacts/tx-os/src/pages/executive-meetings.tsx
  - Removed the inter-person chip render block (the `<li>` + `<button>`
    that used data-testid="em-add-person-after-row-*" /
    data-testid="em-add-person-after-*"). Left a short comment in place
    of the removed block explaining what was there and why it went.
  - Removed the now-unused `addPersonHereLabel` from the props type, the
    component's destructured parameters, and the parent's `t(...)` call.
- artifacts/tx-os/src/locales/en.json + ar.json
  - Removed the orphaned `executiveMeetings.schedule.addPersonHere` key.

Out of scope (per plan, untouched):
- The "+ subheading" / "+ عنوان فرعي" inter-row chip that appears just
  before a subheading row.
- The trailing "+ Virtual" / "+ Internal" / "+ External" add chips that
  appear when a group is empty.
- The per-row trailing "+" button and the inline add-row flow.

Verification:
- TypeScript: clean.
- e2e (testing skill): on /executive-meetings, the page contains zero
  elements matching the old chip's data-testid prefixes and zero
  occurrences of the literal text "+ شخص هنا" or "+ person here", while
  the schedule and attendee lists render normally.

artifacts/tx-os/src/locales/ar.json

@@ -1115,7 +1115,6 @@
       "timeEndShort": "الانتهاء",
       "timeOrderError": "وقت النهاية قبل وقت البداية",
       "addAttendee": "أضف حاضر",
-      "addPersonHere": "+ شخص هنا",
       "addSubheading": "+ عنوان فرعي",
       "addVirtualAttendee": "+ حاضر عبر الاتصال المرئي",
       "addInternalAttendee": "+ حاضر داخلي",

artifacts/tx-os/src/locales/en.json

@@ -1033,7 +1033,6 @@
       "timeEndShort": "End",
       "timeOrderError": "End time is before start time",
       "addAttendee": "Add attendee",
-      "addPersonHere": "+ person here",
       "addSubheading": "+ subheading",
       "addVirtualAttendee": "+ Virtual",
       "addInternalAttendee": "+ Internal",

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

@@ -3689,7 +3689,6 @@ function AttendeesCell({
     onCommitAdd: commitAdd,
     onCancelAdd: cancelAdd,
     addLabel: t("executiveMeetings.schedule.addAttendee"),
-    addPersonHereLabel: t("executiveMeetings.schedule.addPersonHere"),
     addSubheadingLabel: t("executiveMeetings.schedule.addSubheading"),
     editAriaLabel: t("executiveMeetings.schedule.editAttendeeAria"),
     newAriaLabel: t("executiveMeetings.schedule.newAttendeeAria"),
@@ -3884,7 +3883,6 @@ type AttendeeFlowSharedProps = {
   ) => Promise<void>;
   onCancelAdd?: () => void;
   addLabel: string;
-  addPersonHereLabel: string;
   addSubheadingLabel: string;
   editAriaLabel: string;
   newAriaLabel: string;
@@ -3936,7 +3934,6 @@ function AttendeeFlow({
   onCommitAdd,
   onCancelAdd,
   addLabel,
-  addPersonHereLabel,
   addSubheadingLabel,
   editAriaLabel,
   newAriaLabel,
@@ -4246,32 +4243,13 @@ function AttendeeFlow({
         const nextIsSubheading =
           nextItemForPerson &&
           (nextItemForPerson.a.kind ?? "person") === "subheading";
-        // #222: inter-person "+ شخص هنا" chip — appears in the gap
-        // between two consecutive PERSON rows (not before a subheading,
-        // since the after-section subheading chip already lives there).
-        // insertAtIndex = i + 1 so the new person lands immediately
-        // after the current row.
-        if (showAdd && nextItemForPerson && !nextIsSubheading) {
-          nodes.push(
-            <li
-              key={`add-person-after-${i}`}
-              className="basis-full flex justify-center print:hidden"
-              data-testid={`em-add-person-after-row-${i}`}
-            >
-              <button
-                type="button"
-                onClick={() =>
-                  onStartAdd!(addType, "person", i + 1)
-                }
-                data-testid={`em-add-person-after-${i}`}
-                aria-label={addPersonHereLabel}
-                className="text-[10px] text-blue-600 hover:text-blue-700 hover:bg-blue-50 rounded-full px-2 py-0.5 min-h-[1.25rem] border border-dashed border-blue-300 hover:border-blue-500 transition-colors"
-              >
-                {addPersonHereLabel}
-              </button>
-            </li>,
-          );
-        }
+        // The inter-person "+ person here" chip used to live here
+        // (originally added in #222). It was removed in #299: with one
+        // chip rendered between every pair of person rows the cell
+        // looked noisy and repetitive, and the trailing "+" button at
+        // the end of the list already covers the add-person flow.
+        // The "+ subheading" chip just before a subheading row is
+        // preserved below.
         if (showAdd && nextIsSubheading) {
           nodes.push(
             <li