feat(core): expose `Question.ask` via API/SDK

[eXamadeus]

What does this PR do?

Fixes: #8384

Exposes a new POST /question/ask server endpoint that allows clients and the SDK to programmatically ask questions to users without blocking. Key changes:

• Refactored Question.ask() function to support an optional options parameter with an awaitAnswers key:
  • When awaitAnswers: true (default): blocks and returns the answers (existing behavior)
  • When awaitAnswers: false: returns the question request ID immediately without waiting for answers
• Added new /question/ask API endpoint that creates a question request and returns its ID, enabling async question flows from external clients
  • /question/ask endpoint performs session existence validation and returns 404 when the session doesn't exist
• Extracted Question.AskInput schema from Question.Request to provide a clean input type for the new endpoint (without the server-generated id field)
• Regenerated SDK with the new Question.ask() method and types (QuestionAskInput, QuestionAskResponses, etc.)

How did you verify your code works?

• Called endpoint locally and tested with my plugin
• Added a test for the Question.ask refactor in test/question/question.test.ts
• Added server endpoint tests in test/server/question.test.ts:
  • Happy path: returns question ID and adds to pending list
  • Returns 404 when session does not exist
  • Returns 400 when session ID format is invalid
  • Returns 400 when header exceeds max length (12 chars)