fix(browser): update worker format and add e2e test

[CPunisher]

Summary

1. Remove lazyCompilationMiddleware support in @rspack/browser
2. Change the format of worker entry from esm to iife to fix the imported rslib runtime errors.
3. Add basic-react e2e for @rspack/browser

Checklist

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

[netlify]

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[Copilot]

Pull request overview

This PR updates the @rspack/browser package to fix worker format issues and adds basic end-to-end testing. The changes address runtime errors by switching the worker entry format from esm to iife and properly handling lazy compilation middleware for browser environments.

Changes:

• Changed worker entry format from esm to iife in rslib.browser.config.mts to resolve rslib runtime import errors
• Added middleware stub for lazy compilation that throws an error since it's not supported in browser environments
• Added basic-react e2e test case for @rspack/browser with conditional test directory switching based on WASM environment variable

Reviewed changes

Copilot reviewed 10 out of 11 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/rspack/rslib.browser.config.mts	Updated worker format from esm to iife and added middleware replacement plugin
packages/rspack/src/browser/middleware.ts	Added stub that throws error for unsupported lazy compilation middleware
tests/e2e/playwright.config.ts	Added conditional test directory based on WASM environment variable
tests/e2e/tsconfig.json	Added browser-cases to include paths
tests/e2e/package.json	Added @rspack/browser as dependency
tests/e2e/browser-cases/basic-react/*	New e2e test for @rspack/browser with React app bundling
.github/workflows/reusable-build-test.yml	Added separate e2e job for wasm32-wasi-threads target with WASM=1
pnpm-lock.yaml	Updated to include @rspack/browser in e2e tests

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

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[github-actions]

Rsdoctor Bundle Diff Analysis

Found 5 projects in monorepo, 0 projects with changes.

📊 Quick Summary

Project	Total Size	Change
react-10k	5.7 MB	0
react-1k	825.4 KB	0
react-5k	2.7 MB	0
rome	984.3 KB	0
ui-components	2.1 MB	0

Generated by Rsdoctor GitHub Action

[github-actions]

📦 Binary Size-limit

Comparing f8d1ef1 to chore(lint): bump @rslint/core to 0.2.0 and enable default-param-last rule (#12746) by senze.fan

🙈 Size remains the same at 48.03MB

[codspeed-hq]

Merging this PR will not alter performance

✅ 16 untouched benchmarks
⏩ 1 skipped benchmark¹

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_{Comparing 01-15-fix/browser (f8d1ef1) with main (cd15818)}

Footnotes

1. 1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩