Two bugs found via a live test with two real registered browser softphones:
1. retry_escalation_no_answer() re-resolved the client channel via
_resolve_handoff_channel() -> a live AMI CoreShowChannels round-trip that
can take ~10s. The new mvpcc-transfer dialplan wait window (MusicOnHold,
also ~10s, added to give the backend time to redirect before the final
Hangup) was consistently LOST to this exact same duration: the backend's
AMI Redirect fired against a channel the dialplan had already hung up
('Channel does not exist: PJSIP/...', confirmed in escalation timeline).
Fixed by reusing the actively-maintained AsteriskCallLinkRow.channel_name
directly (unchanged for a PJSIP channel across Redirect between contexts
of the same call) instead of re-discovering it, falling back to the slow
path only if that field is empty.
2. VoiceEventIn.event_type is a pydantic Literal restricted to 6 legacy
values (call.started/ivr.completed/...). None of the Phase 2 event
catalog names (AgentReserved/AgentRinging/AgentNoAnswer/AgentConnected/
TransferCompleted/TransferFailed) were ever in it, so every single
_emit_escalation_event() call has been failing with 422 since Phase 2
shipped (swallowed silently by the broad except there) - confirmed by
calling app._emit_voice_event() directly against the running service.
Extended the Literal to include all six.
arys