Create feature specifications using Specification-Driven Development (SDD) methodology.Use when starting a new feature, documenting requirements, or executing the /specify command.This skill guides the creation of comprehensive feature specifications following the SDDframework's spec-template.md structure. It ensures specifications include all requiredsections, validates completeness, detects domains/agents needed, and prepares for theplanning phase.Triggered by: /specify command, user request for "specification", "requirements","feature spec", or "document requirements".