sm-master

Advanced interactive tutorial for skill-map. Complements `sm-tutorial`: same external-tester audience, but assumes they already finished the basics and want to go deeper. Modular format: the tester picks which modules to run from a menu. Covers (1) a guided tour of the built-in plugins (extractors, analyzers, actions, hooks, formatters, providers), (2) plugin authoring via `sm plugins create` / `sm plugins upgrade`, and (3) settings and view-slots at depth. The skill is invoked from an empty directory, lays its own fixture, and tracks progress in `master-state.yml` for pause/resume. Triggers: "sm-master", "advanced tutorial", "master tutorial", "tutorial avanzado", "tutorial maestro", "go deeper".