Dependency discipline for any ecosystem (pip/pyproject, npm/pnpm, cargo, etc.). Load when adding, upgrading, pinning, or removing a dependency; when reading lock files or version constraints; when diagnosing transitive-dependency breakage ("worked yesterday, broken today", import errors after fresh install); when deciding narrow pin vs floating range; or when auditing whether a new dependency is needed at all. Covers constraint syntax, pin-vs-float decision rules, documenting WHY pins exist, and stdlib-first auditing.
