## What changed
- Replace `send_user_message_async` with `request_user_input_async`, accepting one or more questions with optional suggested answers while allowing the turn to continue.
- Attach structured question metadata to asynchronous agent messages while retaining readable fallback text, and preserve it through app-server events, thread history, and generated schemas.
- Continue enabling the new tool for model catalogs that advertise either the old or new tool name.
## Testing
- Cover tool registration, question validation, emitted items, continued turn execution, history preservation, and backwards-compatible deserialization.
GitOrigin-RevId: ffc49aebde2e854c3c50a122aa52805fec3fc6b3
## What changed
- Move schema types, traversal helpers, and large-schema compaction into
dedicated `json_schema` submodules.
- Keep the public schema types re-exported from the existing module and
colocate focused unit tests with their implementations.
GitOrigin-RevId: 953b96c28ae3880f601b588eb016fa126c438852
rka-oai