fix(lotus): a homeserver stall shorter than the delayed-leave window no longer ends the call (#46)

maximumNetworkErrorRetryCount was sized to min(sync grace period,
leave delay), i.e. 10 s, so the membership manager gave up 20-35 s into
a homeserver stall and showed "Connection lost", even when the server
would keep the membership for 60 s (prod config). Size it to the leave
delay instead: the embedded call has no /sync loop for the grace period
to describe, and the server's delayed leave is what actually ends the
membership.

Fixes #46

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

src/state/CallViewModel/localMember/LocalMember.ts

@@ -868,16 +868,19 @@ export function enterRTCSession(
     };
   }
 
-  // Calculates `maximumNetworkErrorRetryCount`. The connection is failed if EITHER:
-  // - The /sync loop is unresponsive for > `gracePeriod` ms, or
-  // - A delayed leave event is emitted (after `leaveDelay` ms period).
-  // Note: Use leaveDelay >> gracePeriod for delegated leave events.
+  // Calculates `maximumNetworkErrorRetryCount`: enough retries to outlast the
+  // server's delayed-leave window (see [lotus #46] below).
   const gracePeriod = Config.get().sync_disconnect_grace_period_ms;
   const leaveDelay = matrixRtcSessionConfig?.delayed_leave_event_delay_ms;
   const retryInterval = matrixRtcSessionConfig?.network_error_retry_ms;
 
-  // Math.min is used to account for the respective worst case: /sync not available or leave event emitted.
-  const maxWaitTime = Math.min(gracePeriod, leaveDelay);
+  // [lotus #46] Keep retrying for as long as the homeserver itself would keep
+  // our membership: until its delayed leave fires (`leaveDelay`). Capping at
+  // the 10 s sync grace period made a ~20–35 s homeserver stall end everyone's
+  // call ("Connection lost") even with a 60 s server-side leave delay. The
+  // embedded call has no /sync loop of its own, so the grace period doesn't
+  // describe anything it can observe.
+  const maxWaitTime = Math.max(gracePeriod, leaveDelay);
   const maximumNetworkErrorRetryCount =
     Math.ceil(maxWaitTime / retryInterval) + 1;