feat: SSE live ping stream for monitors

apps/web/src/dashboard/app.js

@@ -93,3 +93,21 @@ function escapeHtml(str) {
   div.textContent = str;
   return div.innerHTML;
 }
+
+// Subscribe to live ping updates for a monitor via SSE
+// onPing(ping) called with each new ping object
+function watchMonitor(monitorId, onPing) {
+  const key = localStorage.getItem('pingql_key');
+  if (!key) return null;
+
+  const url = `/monitors/${monitorId}/stream`;
+  const es = new EventSource(url + `?auth=${encodeURIComponent(key)}`);
+
+  es.onmessage = (e) => {
+    try { onPing(JSON.parse(e.data)); } catch {}
+  };
+  es.onerror = () => {
+    // Reconnect is automatic with EventSource
+  };
+  return es;
+}