feat(calls): "Call ended · 41 min · connection was good" toast (#143)

One line in the existing toast style when a call you were in ends: the
duration from our own join clock, plus the fork's io.lotus.call_summary
readout (fork ≥ 0.25.0-lotus.10) when it arrives — "connection was
good", "3 reconnects", "connection was poor for 4 min". Nothing is
stored or sent; the summary is one postMessage at hangup. Without the
fork summary the toast still shows the duration.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/hooks/useCallEndedToast.ts

@@ -0,0 +1,40 @@
+import { useEffect, useRef } from 'react';
+import { useSetAtom } from 'jotai';
+import { CallEmbed } from '../plugins/call';
+import { useCallHangupEvent } from './useCallEmbed';
+import { toastQueueAtom } from '../state/toast';
+import { describeCallEnd } from '../utils/callSummary';
+
+// The fork sends io.lotus.call_summary on SFU disconnect, which normally lands
+// before Element Call's hangup echo; give a late one this long before toasting.
+const SUMMARY_GRACE_MS = 400;
+
+/**
+ * [Gitea #143] "Call ended · 41 min · connection was good" in the existing
+ * toast style when a call you were in ends. Duration comes from our own
+ * join clock; the quality readout from the fork, if it arrived.
+ */
+export function useCallEndedToast(embed: CallEmbed): void {
+  const setToast = useSetAtom(toastQueueAtom);
+  const fired = useRef(false);
+
+  useEffect(() => {
+    fired.current = false;
+  }, [embed]);
+
+  useCallHangupEvent(embed, () => {
+    if (fired.current || !embed.joined || embed.joinedAt === undefined) return;
+    fired.current = true;
+    const durationMs = Date.now() - embed.joinedAt;
+    const toast = () =>
+      setToast({
+        id: `call-ended-${Date.now()}`,
+        displayName: 'Lotus Chat',
+        body: describeCallEnd(durationMs, embed.lastSummary),
+        roomName: embed.room.name ?? 'Voice call',
+        roomId: embed.roomId,
+      });
+    if (embed.lastSummary) toast();
+    else setTimeout(toast, SUMMARY_GRACE_MS);
+  });
+}