Guided authoring for immutable, append-only PRD/pitch files. Conducts a grill-me style interview with context intake, domain-language check, multi-persona adversarial review, and a 90% completeness gate before writing any file. In a repo that opts into the requirement contract, also reads the bound tracker ticket's binding sections, judges each item, and records disagreements the validator gates on. Use when a team needs to produce new spec/PRD content or version-update existing ones in an append-only SDD repo. Triggers - "/immutable:prd", "pitch 작성", "스펙 작성", "PRD 추가", "피치 만들어".
