Agent Skills: requirements-gap-filler

Checks requirements.md against the actual codebase to find ALL four types of gaps — requirements missing from code, requirements partially implemented, code logic not mentioned in requirements, and business rules in code that were never written into requirements. Automatically updates requirements.md in both directions — flags unimplemented requirements AND adds newly discovered code logic back into requirements. Use after code generation to keep requirements fully in sync with what was actually built.