async function startMonitor() {
    if (!MON.id) return;
    stopStream();
    const body = $("#monBody");
    body.innerHTML = `<div class="skeleton"></div><div class="skeleton" style="width:60%"></div>`;
    await drawProgress();     // initial paint via REST
    await drawRecipients();
    drawControls();
    // SSE
    MON.es = new EventSource(`/campaigns/${MON.id}/stream`);
    MON.es.addEventListener("connected", () => $("#liveInd").classList.remove("hidden"));
    MON.es.addEventListener("progress", ev => { try { paintProgress(JSON.parse(ev.data)); } catch {} });
    MON.es.addEventListener("done", ev => {
      try { paintProgress(JSON.parse(ev.data)); } catch {}
      stopStream();
      toast(`Campaign finished — status: ${(JSON.parse(ev.data) || {}).status || "?"}`, "info", 6000);
      drawControls();
    });
    MON.es.onerror = () => { $("#liveInd").classList.add("hidden"); };
  }
  async function drawProgress() {