Agent Skills: bundle-size

Attributes a frontend project's JavaScript bundle size to the imports that caused it, then renders a light-theme analytics website. Bundles the app with esbuild, reads the metafile, and reports how many minified KB each npm package and source module added. Use when the user runs /bundle-size or asks which import is the heaviest, what is bloating the bundle, or for a bundle-size / import-cost report.