Show generated code from loaders in parse error messages
When webpack/turbopack loaders return invalid code, the error messages now
show both the original source and the generated code with source map
information, making it easier to debug loader issues.
Core changes:
- Added AdditionalIssueSource infrastructure (turbopack-core)
- Created GeneratedCodeSource wrapper that strips source map support
- Added description() method to Source trait for human-readable source chains
- Updated error formatting in turbopack-cli-utils and packages/next
- Added e2e tests for JS and CSS loader parse errors
Co-Authored-By: Claude <noreply@anthropic.com>
