Add environment parameter to conversational AI

[AngeloGiacco]

Summary

• Adds optional environment parameter to the WebSocket connection URL for conversational AI agents
• Adds optional environment parameter to the get_signed_url and get_webrtc_token API routes (both sync and async clients)
• Adds optional environment parameter to Conversation and AsyncConversation classes, which gets passed through to the WebSocket URL and signed URL endpoints
• Defaults to "production" on the server when not specified

Test plan

• Verify environment query param is appended to WebSocket URL when provided
• Verify environment query param is sent to get_signed_url endpoint
• Verify environment query param is sent to get_webrtc_token endpoint
• Verify no environment param is sent when not specified (backwards compatible)

🤖 Generated with Claude Code