Interview the user about their product idea, analyze responses, ask follow-up questions, and produce
a structured interview brief. Use when starting a new product pipeline or when the user has a raw idea
that needs clarification. This is step 1 of the product development pipeline.
Examples:
- user: "I want to build a medical OCR system" → interview about use cases, users, constraints
- user: "Help me define my startup idea" → conduct structured discovery interview
- user: "Start the product pipeline" → begin with this skill
