Task #696: Key attendees as a table in booking details dialog

- artifacts/tx-os/src/pages/protocol.tsx: replaced the dash-separated
  <ul> list of keyAttendees in the booking details dialog with a shadcn
  Table (already imported) with 3 columns: Name, Position/Title, Side.
  Headers use text-start for correct RTL alignment; empty name/position
  cells render an em dash; side rendered as the existing pill using
  protocol.bookings.attendeeSides.*; table wrapped in rounded border +
  overflow-x-auto so it stays responsive inside the dialog.
- i18n: added protocol.bookings.details.attendeeCols.{name,position,side}
  to ar.json (الاسم/الصفة/الجهة) and en.json (Name/Title/Side).
- Scope limited to the details dialog; the expanded-row attendee display
  elsewhere is unchanged (per task out-of-scope).
- Verified: both locale JSONs valid, tsc --noEmit clean, architect review
  PASS.
- No follow-ups proposed: pending Task #695 already covers e2e testing of
  the details dialog contents.

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

@@ -1796,6 +1796,11 @@
         "meetingSection": "تفاصيل الاجتماع",
         "notes": "ملاحظات",
         "rejectionReason": "سبب الرفض",
+        "attendeeCols": {
+          "name": "الاسم",
+          "position": "الصفة",
+          "side": "الجهة"
+        },
         "source": "مصدر الطلب",
         "sources": {
           "internal": "داخلي",