Turn streaming now propagates the triggering user_message_uuid and tracks first-frame upload

Live thinking_tokens progress frames (stream-json / Agent SDK) are now stamped with user_message_uuid, the client uuid of the user message (submitMessage options.uuid) that triggered the turn, letting a consumer attribute thinking progress to a send before any reply frame arrives. It's absent on synthetic/scheduled turns, turns without a client uuid, and on Remote Control (interactive terminal) sessions. The synthesized result SDK event (built by the new own function) likewise now includes user_message_uuid when available and the outcome isn't a terminal-reason exit.

The turn-streaming generator also now calls an optional trackFirstFrameUpload callback on the first non-thinking stream_event of a turn.