Add generate_reply and update_chat_ctx support to Phonic Plugin

[qionghuang6]

This PR adds support for generate_reply and update_chat_ctx to the Phonic Plugin.

These are implemented in:
livekit/agents-js#1103 and livekit/agents-js#1114 in the Livekit Agents JS repo.

generate_reply was recently added to Phonic as a feature.

For update_chat_ctx, we would like to support 2 scenarios:

• Rehydrating a conversation with chat history when a RealtimeSession begins: For this use case, in situations where the config message has not yet been sent to Phonic, we include the conversation history's roles and text content as an addendum to the system prompt being sent over to Phonic.
• Adding system or developer messages to the conversation history. If we detect that the chat_ctx has been updated to include these messages, we can send them to Phonic using the add_system_message message. This will allow the user to steer the conversation without calling generate_reply

I have also updated the example.

Here's a video demo: https://screen.studio/share/p6wLZbrY

[tinalenguyen]

I tried out the example with phonic==0.31.3 and I get spammed with this error:

  01:24:35.537 WARNI… phonic.c…et_client Skipping unknown WebSocket message; update your SDK version to support new message types.  
  01:24:35.542 WARNI… phonic.c…et_client Skipping unknown WebSocket message; update your SDK version to support new message types.

Should I upgrade anything else or might I be missing something?

[qionghuang6]

I tried out the example with phonic==0.31.3 and I get spammed with this error:

  01:24:35.537 WARNI… phonic.c…et_client Skipping unknown WebSocket message; update your SDK version to support new message types.  
  01:24:35.542 WARNI… phonic.c…et_client Skipping unknown WebSocket message; update your SDK version to support new message types.

Should I upgrade anything else or might I be missing something?

So sorry, there was an issue with today's updated SDK that I just patched.

[tinalenguyen]

lgtm, thank you for the quick late night fix!