Three fixes for multi-instance call state consistency:
1. Client dm_call_accepted handler only auto-connects to LiveKit if
the user was the caller (outgoingCall was set). Other instances of
the same user just clear ringing state without connecting.
2. Server processDmCallAcceptEvent remote path skips duplicate
broadcast when FederatedCallEntry is already active (prevents
state conflicts from host fan-out arriving after local accept).
3. Ready payload handler clears stuck incomingCall when restoring
an already-active call after page refresh.
Jannis Braun
9ad240495f