Adds 16 project skills (plus 3 runnable diagnostic scripts) that encode
the project's architecture contracts, backend capability matrix, storage
and migration protocols, build/run/debug runbooks, failure archaeology,
Lightning domain reference, and research discipline, so contributors and
AI coding sessions can operate at maintainer standard without rederiving
project knowledge.
All facts were verified against master c5fd094fb and adversarially
reviewed (factual/doctrine/usability passes) before inclusion. Also
updates .gitignore to share .claude/skills/ while keeping all other
.claude/ files (e.g. settings.local.json) local.