Questionnaire Plugin (migrated from Pi ecosystem questionnaire.ts & question.ts).

Adds the ask_question tool. A call publishes the questions as a ui_request event and waits for a client to answer (SuperPi.UI.Broker). The CLI chat asks on the terminal. An RPC client that watches the conversation receives the event and answers with ui.respond.

• With no client able to answer (the HTTP gateway, a headless run), the call returns an error at once. The model is not given invented answers.
• The wait ends after config :super_pi, questionnaire_timeout_ms (default 10 minutes) or when the conversation is cancelled.
• A pending question is not stored. After a crash the turn restarts and the model asks again.
• ctx[:questionnaire_answers] (a map of question text to selected option) answers without asking. It is for headless runs and tests, and the output says the answers were preset.

While a question waits, the conversation process is blocked in the tool call, so a steer message is handled only after the answer. session.cancel ends the wait.