1. Adds AgentMessage, Reasoning, WebSearch items. 2. Switches the ResponseItem parsing to use new items and then also emit 3. Removes user-item kind and filters out "special" (environment) user items when returning to clients.
1. Adds AgentMessage, Reasoning, WebSearch items. 2. Switches the ResponseItem parsing to use new items and then also emit 3. Removes user-item kind and filters out "special" (environment) user items when returning to clients.