Refine Product Requirement Document

Update it_{current_iteration}_product-requirement-document.md in place based on user feedback. The file must already exist; this skill does not create it from scratch.

Do NOT start implementing. Only update the document.

Two modes available — the agent asks at the start:

• Editor mode — apply specific changes requested by the user.
• Challenger mode — act as an independent critical reviewer: challenge assumptions, question scope, find gaps, and propose improvements. The user accepts or rejects each suggestion before anything is written.

Reasoning Protocol

Use Chain of Draft (CoD) for all internal reasoning steps performed while executing this skill.