perf(cli): reduce fs calls in crossImport function

[chenjiahan]

Summary

Refactors the config file loading logic to use a single import()instead of manually distinguishing between ESM and CommonJS modules.

Before

Rspack determined whether to use require() or import() by checking file extensions and walking up the directory tree to read the nearest package.json to detect "type": "module". This introduced unnecessary complexity and I/O overhead.

After

All config files are now loaded through a unified import() call (the same as Rsbuild), then fallback to require().

This approach leverages Node.js's native module resolution to automatically handle both ESM and CommonJS formats.

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[Copilot]

Pull Request Overview

This PR refactors the config file loading logic to use a single unified import() call instead of manually distinguishing between ESM and CommonJS modules. This reduces filesystem I/O overhead by eliminating the need to check file extensions and walk up the directory tree to detect module types.

Key changes:

• Removed the separate crossImport utility file and inlined a simplified version using pathToFileURL
• Updated all crossImport() calls to remove the cwd parameter
• Leverages Node.js's native module resolution to automatically handle both ESM and CommonJS formats

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[github-actions]

📦 Binary Size-limit

Comparing 9e55c15 to chore: enable Rslint rule: no-empty-interface (#11915) by Dima Shugaev

🙈 Size remains the same at 47.73MB

[codspeed-hq]

CodSpeed Performance Report

Merging #11933 will not alter performance

_{Comparing load_config_perf_1020 (9e55c15) with main (e3199f4)}

Summary

✅ 17 untouched

[netlify]

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