fix(calls): Reject sends the decline to the ring notification (#313)

handleReject related the MSC4310 decline to the caller's call.member event
(the notification's reference), but MSC4310 and Element Call match a
decline against the rtc.notification event itself, so the caller kept
"Calling…" for the full 90 s after being told "Declined", and declines
from other clients (correctly referencing the notification) didn't stop
Lotus ringing on other devices.

- The incoming call keeps the notification's own event id; Reject relates
  the decline to it.
- The "declined on another device" dismissal and declinedRing accept
  either id (older Lotus builds referenced the membership).
- The missed-call line is skipped for a call we declined.

Verified headless (DM, Bob rings, Reject): the decline used to reference
the membership; it now references the notification. Unit test added.

Fixes #313

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/components/CallEmbedProvider.tsx

@@ -111,6 +111,8 @@ type IncomingCallInfo = {
   intent?: string;
   notificationType: RTCNotificationType;
   refEventId: string;
+  /** [Gitea #313] The rtc.notification event itself: what a decline must reference (MSC4310). */
+  notificationEventId?: string;
 };
 type IncomingCallProps = {
   dm: boolean;
@@ -283,7 +285,9 @@ function IncomingCall({ dm, info, onIgnore, onAnswer, onReject }: IncomingCallPr
                   fill="Soft"
                   size="400"
                   radii="400"
-                  onClick={() => (dm ? onReject(room, info.refEventId) : onIgnore())}
+                  onClick={() =>
+                    dm ? onReject(room, info.notificationEventId ?? info.refEventId) : onIgnore()
+                  }
                   before={<Icon size="200" src={Icons.Cross} filled />}
                 >
                   <Text as="span" size="B400">
@@ -455,7 +459,9 @@ function IncomingCallBanner({ dm, info, onIgnore, onAnswer, onReject }: Incoming
           size="300"
           radii="300"
           outlined
-          onClick={() => (dm ? onReject(room, info.refEventId) : onIgnore())}
+          onClick={() =>
+            dm ? onReject(room, info.notificationEventId ?? info.refEventId) : onIgnore()
+          }
           before={<Icon size="100" src={Icons.Cross} filled />}
         >
           <Text as="span" size="B300">
@@ -596,6 +602,7 @@ function IncomingCallListener({ callEmbed, joined }: IncomingCallListenerProps)
             : undefined,
         notificationType,
         refEventId,
+        notificationEventId: event.getId(),
       };
 
       // [Gitea #312] Don't ring for a call that is already over or handled: after
@@ -604,7 +611,10 @@ function IncomingCallListener({ callEmbed, joined }: IncomingCallListenerProps)
       // stale RTC session). The caller's membership can arrive just after the
       // ring, so an absent one gets a short grace period before giving up.
       const myUserId = mx.getSafeUserId();
-      if (declinedRing(room, refEventId, myUserId) || hasActiveCallMembership(room, myUserId)) {
+      if (
+        declinedRing(room, [refEventId, event.getId()], myUserId) ||
+        hasActiveCallMembership(room, myUserId)
+      ) {
         return;
       }
       if (hasActiveCallMembership(room, sender)) {
@@ -613,7 +623,10 @@ function IncomingCallListener({ callEmbed, joined }: IncomingCallListenerProps)
       }
       setTimeout(() => {
         if (Date.now() >= senderTs + lifetime) return;
-        if (declinedRing(room, refEventId, myUserId) || hasActiveCallMembership(room, myUserId)) {
+        if (
+          declinedRing(room, [refEventId, event.getId()], myUserId) ||
+          hasActiveCallMembership(room, myUserId)
+        ) {
           return;
         }
         if (hasActiveCallMembership(room, sender)) setCallInfo(info);
@@ -685,7 +698,10 @@ function IncomingCallListener({ callEmbed, joined }: IncomingCallListenerProps)
       if (eventRoom?.roomId !== room.roomId || !data.liveEvent) return;
       if (event.getType() === EventType.RTCDecline && event.getSender() === myUserId) {
         const related = event.getRelation()?.event_id;
-        if (!related || related === refEventId) dismiss(); // declined elsewhere
+        // [Gitea #313] Correct clients reference the notification; older Lotus
+        // builds referenced the call membership. Accept both.
+        if (!related || related === refEventId || related === callInfo.notificationEventId)
+          dismiss(); // declined elsewhere
       }
     };
     session.on(MatrixRTCSessionEvent.MembershipsChanged, checkMemberships);