[MatthewHsu1]

Change

• AgentHook. Hosts can now see and gate the run. There are gates (Hooks.Gates) and notices (Hooks.Notices), with a HookScope for each call.
• GPT-Live phone path. A GPT-Live call now runs through PhoneCall. It can greet first, and its greeting and settings come from configuration.
• Conversation actions. A tool can ask the channel to act on the call through IConversationChannel. The answer is a ConversationActionResult.
• Call transfer. TransferAction moves a GPT-Live call to another line. The transfer waits until the caller has heard the answer.
  • The default is OpenAI's SIP refer. OpenAI never reports the result of a REFER (probe T1). So when the peer closes the AI leg within the wait, the transfer worked.
  • A host can register its own ICallTransfer as a singleton. Its answer (Taken / NotTaken) is the outcome.
  • With TransferAction.IfFailed set, a failed transfer does not hang up. GPT-Live says the host's words, and the call goes on.
• Routing and authentication for the Telnyx and OpenAI Live vendors.

Public API

All changes add API. Nothing in PublicAPI.Shipped.txt was removed.

Tests

OpenAiLiveTransferTests covers a refer the peer accepts, a refer it refuses, a host transfer that was taken, a host transfer that failed (the call goes on), and a call that cannot transfer.