Rspack support needs unit tests

[Judahmeek]

Right now, all the rspack exports are not verified to work correctly & some, like baseConfig, definitely do not.

We need to create Jest unit tests that test all of our node package's public API exports.

[justin808]

Fixed in PR #846

Added comprehensive Jest unit tests for rspack support covering all public API exports:

• Main rspack module exports and configuration generation
• Plugin system (RspackManifestPlugin, CssExtractRspackPlugin, SubresourceIntegrityPlugin)
• Optimization configuration (SwcJsMinimizerRspackPlugin, LightningCssMinimizerRspackPlugin)
• Loader rules (JavaScript/TypeScript SWC loader, CSS/Sass/Less/Stylus, ERB, asset handling)

All 61 tests passing ✅