fix: avoid chunk conflicts when multiple libs are present

[fi3ework]

Summary

to fix the case added in test cases, multi-compiler don't know other compilers' existence, so it's prone to emit chunk file to same path, whereas the content might not the same. this it's not prone to happen in Rsbuild as the hash is enabled but hash is disabled in Rslib.

Related Links

Checklist

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

[Copilot]

Pull Request Overview

Fixes chunk filename conflicts in multi-compiler builds by adding index prefixes to chunk filenames. This prevents multiple compilers from generating chunks with identical filenames that could overwrite each other when hash is disabled.

• Added composeOutputConfig function to prefix chunk filenames with compiler index in multi-compiler scenarios
• Updated composeLibRsbuildConfig and composeCreateRsbuildConfig to pass compiler index information
• Added comprehensive test cases for both single and multi-compiler chunk naming scenarios

Reviewed Changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
packages/core/src/config.ts	Added output config composition and multi-compiler index tracking
tests/integration/output/index.test.ts	Added test cases for chunk filename behavior verification
tests/integration/output/chunkFileName-multi/	Multi-compiler test fixture with shared dependencies
tests/integration/output/chunkFileName-single/	Single-compiler test fixture for baseline comparison
packages/core/tests/snapshots/config.test.ts.snap	Updated snapshots reflecting new chunk filename patterns

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

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[Copilot]

Pull Request Overview

Copilot reviewed 14 out of 15 changed files in this pull request and generated 2 comments.

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

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