Agent Skills: composer-patch-generator

Generate and maintain patches for Composer-installed packages (Drupal contrib modules, WordPress packages, PHP libraries) using cweagans/composer-patches. Invoke when the user needs to modify a contrib or vendor package, mentions "composer patch", "patch a module", "patch a contrib module", "cweagans", "diff -ruN", "extra.patches", or needs a package change that applies cleanly in CI. Covers generating diff -ruN patches, handling new files, wiring composer.json, and verifying the patch applies.