feat!: migrate to esm-only

[kettanaito]

Migrates MSW to be ESM-only 🎉 Finally.

[coderabbitai]

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[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@​commitlint/​cli@​21.2.1
	@​types/​serviceworker@​0.0.199
	@​fastify/​websocket@​11.3.0
	tsdown@​0.22.9
	tough-cookie@​6.0.2
	oxlint@​1.73.0 ⏵ 1.74.0	+1		+1
	knip@​6.27.0
	@​commitlint/​config-conventional@​21.2.0
	prettier@​3.9.5
	lint-staged@​17.1.0

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[pkg-pr-new]

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npm i https://pkg.pr.new/msw@2765

commit: dabe4b3

[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@config/plugins/rolldown/forceFileExtensionsPlugin.ts`:
- Around line 21-35: Update ESM_RELATIVE_IMPORT_EXP and modifyRelativeImports to
rewrite both from-clause and side-effect relative imports, while preserving
existing non-JavaScript extensions such as .json instead of appending
ESM_EXTENSION. Retain directory handling with /index and support
import-attribute syntax, then add coverage for side-effect, JSON, directory, and
import-attribute cases before publishing chunks.

In `@config/plugins/rolldown/resolveCoreImportsPlugin.ts`:
- Around line 3-31: Update resolveCoreImportsPlugin and replaceCoreImports so
the rewritten `#core` import path is calculated relative to each emitted chunk’s
fileName rather than hardcoding ../core. Pass the chunk fileName into the
replacement logic and preserve the existing submodule and semicolon handling
while resolving the correct relative path for nested output chunks.

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📥 Commits

Reviewing files that changed from the base of the PR and between 5283bf7 and dabe4b3.

⛔ Files ignored due to path filters (1)

• pnpm-lock.yaml is excluded by !**/pnpm-lock.yaml

📒 Files selected for processing (20)

• .oxlintrc.json
• browser/package.json
• cli/package.json
• commitlint.config.js
• config/package.json
• config/plugins/rolldown/copyWorkerPlugin.ts
• config/plugins/rolldown/forceFileExtensionsPlugin.ts
• config/plugins/rolldown/resolveCoreImportsPlugin.ts
• config/replaceCoreImports.js
• config/scripts/patch-ts.js
• config/scripts/postinstall.js
• graphql/package.json
• native/package.json
• node/package.json
• package.json
• src/package.json
• test/modules/node/esm-node.test.ts
• test/support/alias.ts
• test/support/msw-esm/package.json
• tsdown.config.mts

💤 Files with no reviewable changes (10)

• config/replaceCoreImports.js
• node/package.json
• cli/package.json
• src/package.json
• config/scripts/patch-ts.js
• browser/package.json
• graphql/package.json
• config/package.json
• native/package.json
• test/support/msw-esm/package.json