prd-authoringlisted

# Foundation: PRD Authoring ## What it does SPECTER has thorough PRD *auditing* (`/ms.featuremap`, `/ms.checklist`, `/ms.verify`) but no PRD-*authoring* support — until now. This skill co-writes a PRD with the user through a guided interview, in a form the rest of the pipeline can consume without rework: - Every requirement is a **commitment** in the vocabulary `/ms.featuremap` already extracts from (functional requirement, user journey, milestone, constraint, acceptance criterion, NFR, integration promise, migration/data requirement, or explicit exclusion) — not vague prose. - A dedicated **Testing Decisions** section identifies the seam each major commitment will be tested at, feeding the Done Criteria Execution gate (`/ms.review` Step 6.6) downstream instead of that decision surfacing for the first time at implementation. - Gaps are tagged inline as they're found (🔶 Assumption / 🔵 Open Question), not buried in a closing "questions" section nobody re-reads. ## When to use - No PRD exists yet and the user wants to co-author one before `/ms.pre-specter`. - Extending an existing PRD: produce a `## PRD Amendment N — YYYY-MM-DD` section appended to the end of the file (never edit prior sections), matching the format `/ms.expand` consumes. - The user has scattered notes/a conversation's worth of context and wants it turned into a structured PRD rather than starting from a blank page. ## How it works ### 0. Calibrate on the user's unknowns first The gap bet