[#6] Add admin panel at /admin

- Password-protected (cabo2026) admin page
- View/approve/reject pending options
- Delete any option
- Toggle polls open/closed
- Live stats: voters, options, votes, pending count
- Add DELETE /api/options/:id endpoint
- Add option_deleted WebSocket broadcast

public/index.html

@@ -780,6 +780,10 @@
           renderTabs();
           render();
         }
+      } else if (msg.type === 'option_deleted') {
+        state.options = state.options.filter(o => o.id !== msg.id);
+        renderTabs();
+        render();
       } else if (msg.type === 'polls_status') {
         state.pollsOpen = msg.open;
         updatePollsBadge();