fix: always include parameters in Genesys AudioHook messages

[poislagarde]

Summary

The AudioHook protocol requires every message to include a parameters object (even if empty {}). The _create_message method conditionally included it only when parameters were truthy:

if parameters:
    msg["parameters"] = parameters

This meant pong responses and closed responses without outputVariables were sent without a parameters field at all.

The Genesys reference client validates every incoming message with isMessageBase, which requires isJsonObject(msg['parameters']). Without the field, the message fails validation and triggers a fatal protocol error. This causes a cascade:

1. Client rejects the pong → doesn't update its serverseq tracker
2. Next message (closed) arrives with a higher-than-expected seq → protocol error
3. Client rejects closed → outputVariables never reach the Architect flow

Fix

msg["parameters"] = parameters if parameters is not None else {}

Testing

• All 28 existing Genesys serializer unit tests pass (updated 2 to match new behavior)
• Tested against the Genesys AudioHook reference implementation test client (client/). Before the fix, the client logged Protocol error: Current serverseq=1 and incoming message has seq=3 and the session ended in CLOSING-ERROR. After the fix, the session completes cleanly:

INFO: onOpenedMessage - Session open! Parameters: {"startPaused":false,"media":[...],"selectedLanguage":"en-US"}
INFO: onPongMessage - rtt: 3.8ms
INFO: Source stream ended (duration: PT3S), closing session.
INFO: onClosedMessage - Session closed (state: CLOSING)
INFO: All sessions disconnected, exiting

Changelog

Included as changelog/0000.fixed.md — happy to rename to the PR number once assigned.

🤖 Generated with Claude Code

[markbackman]

LGTM! Thanks for the contribution 🙇

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
src/pipecat/serializers/genesys.py	77.67% <100.00%> (-0.07%)	⬇️

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