Standalone single-spa webpack plugin

A webpack plugin that enables running single-spa microfrontends in standalone mode for development, as an alternative to import-map-overrides. Current stable version is 6.0.0, released with breaking changes: moduleFormat now defaults to ESM instead of SystemJS, and HtmlWebpackPlugin option is now required. The plugin rewrites the microfrontend's HTML and JS to load and mount it as a standalone single-spa application or parcel, with support for import maps, custom props, and start options. It ships TypeScript types and requires webpack and html-webpack-plugin as peer dependencies. Key differentiators: built specifically for single-spa ecosystem, supports ESM and SystemJS module formats, integrates with import-map-overrides UI, and provides a local development experience that simulates the microfrontend being part of a larger single-spa application. However, it is not equivalent to integrated mode and has known pitfalls such as updated single-spa/SystemJS versions and missing global styles/scripts.