feat: add experimental ESM output support for node target

[chenjiahan]

Summary

Add output.module config to enable experimental ESM output format when target is node. This includes adding a new plugin to handle ESM-specific Rspack configurations and updating related type definitions and test cases.

The feature is marked as experimental and currently only supports node target. This provides a foundation for future ESM support in other targets.

export default {
  output: {
    module: true,
  }
}

Related Links

• docs(ESM): add ESM guide rspack#11344
• https://rspack.rs/config/output#outputmodule

Checklist

• Tests updated (or not required).
• Documentation updated (or not required). -> will be added in future PRs

[Copilot]

Pull Request Overview

Adds experimental ESM output support for node targets by introducing a new output.module configuration option. This enables developers to generate JavaScript files in ES modules format when targeting Node.js environments.

• Introduces a new output.module boolean configuration option to enable ESM output
• Implements a new ESM plugin that automatically configures Rspack for ESM output when enabled
• Updates existing test configurations to use the new simplified ESM configuration

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/core/src/types/config.ts	Adds module property to output configuration types with experimental annotation
packages/core/src/plugins/esm.ts	New plugin implementing ESM-specific Rspack configurations and node target validation
packages/core/src/defaultConfig.ts	Sets default value for module configuration to false
packages/core/src/createRsbuild.ts	Registers the new ESM plugin in the default plugin list
e2e/cases/server/ssr/rsbuild.config.ts	Updates test to use simplified ESM configuration
e2e/cases/server/ssr-type-module/rsbuild.config.ts	Replaces manual Rspack configuration with new ESM option

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