Clearing a notification settles what it was about; fix missed phone pushes

Reading or clearing a notification marks its chat and new mail read and closes its banner; opening a chat clears its entry. Close the chat stream while the app is hidden so the server sends the phone push, renew changed push subscriptions, and re-send the subscription on each app open.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

public/chat-view.js

@@ -17,6 +17,10 @@ async function chStart() {
   ch.es = new EventSource('/api/chat/events');
   ch.es.onmessage = e => { let ev; try { ev = JSON.parse(e.data); } catch { return; } chEvent(ev); };
 }
+// (iOS keeps a suspended app's connection open for minutes, and the server skips the phone push for anyone it thinks is looking: close the stream whenever the app is hidden)
+const chHide = () => { if (ch.es) { ch.es.close(); ch.es = null; } };
+document.addEventListener('visibilitychange', () => { if (document.hidden) chHide(); else chStart(); });
+window.addEventListener('pagehide', chHide);
 let chEvT = null;
 function chEvent(ev) {
   if (typeof ev.unread === 'number' && ev.unread !== ch.unread) { ch.unread = ev.unread; renderNav(activeTab); }