chore(deps): bump protocol for simulation job failure_reason, call facts and turn text

[u9g]

Depends on livekit/protocol#1867. go.mod points at its commit; before this merges, it should be bumped to the protocol release that includes it.

lk agent simulate export writes the run with protojson, using the CLI's own copy of the protocol types. Any field the CLI doesn't know about is left out of the JSON, even when the server sends it. This bump lets the export keep these fields, which livekit/agents-private#555 fills on the server:

Field	What it is
jobs[].failure_reason	the machine-readable cause of a failed job, such as FAILURE_REASON_AGENT_JOIN_TIMEOUT
jobs[].metrics.end_reason, caller_language, caller_listen_language, impairments, conversation.backchannel_count	how the call ended and what the caller sounded like
jobs[].metrics.turns[].text	each turn's words, as the simulation's judges read them

There's no other code change: the export already serializes SimulationRun generically.

Tested

go test -tags portaudio_system ./cmd/lk/ -run Simulat passes. The video below exports runs from a local agent-service built from livekit/agents-private#555.

[u9g]

lk agent simulate export built from this PR, against a local agent-service from livekit/agents-private#555, shows each job's new failure_reason, call facts (end_reason, caller_language, caller_listen_language, impairments, conversation.backchannel_count) and turns[].text; lk built from main exports the same run with all of them missing.

export-fields.mp4