Upgrade MSW from 1.3.5 to 2.12.4

[madsrasmussen]

The PR upgrades MSW to the latest version. The migration of interceptors has been done with the help of Claude.

Handler syntax migration (113 files)

• rest → http namespace
• res(ctx.status(), ctx.json()) → HttpResponse.json()
• Handler signatures: (req, res, ctx) => {} → ({ request, params }) => {}

Backoffice integration (index.ts)

• Wrapped bootstrap in an async function to await startMockServiceWorker() before app starts

Test runner (web-test-runner.config.mjs, web-test-runner.index.ts)

• Changed to sequential module loading with dynamic imports
• Ensures MSW service worker is ready before the tests execute

Other

• Regenerated mockServiceWorker.js

What to test:

• Please make sure that the mocked backoffice still works
• Please make sure that the storybook build stil works

[Copilot]

Pull request overview

This pull request upgrades Mock Service Worker (MSW) from version 1.3.5 to 2.12.4, involving a comprehensive migration from MSW v1 to v2 API patterns. The migration includes updating 113 handler files to use the new http namespace instead of rest, changing response construction from res(ctx.*) to HttpResponse constructors, and modifying handler signatures from (req, res, ctx) to destructured parameters ({ request, params }). The PR also updates the test infrastructure to ensure MSW is properly initialized before tests run.

Key Changes

• Updated MSW package dependency from ^1.3.5 to ^2.12.4
• Migrated 113+ handler files from MSW v1 to v2 API syntax
• Regenerated mockServiceWorker.js with v2 implementation
• Updated test runner configuration to load MSW sequentially with await
• Modified type imports to use v2 module paths (msw/browser)

Reviewed changes

Copilot reviewed 120 out of 121 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
package.json	MSW version bump from 1.3.5 to 2.12.4
public/mockServiceWorker.js	Regenerated service worker with v2 implementation
web-test-runner.index.ts	Added await to worker.start() call
web-test-runner.config.mjs	Sequential async module loading to ensure MSW ready before tests
src/mocks/index.ts	Updated type imports to msw/browser and msw modules
src/mocks/handlers/**/*.handlers.ts	Migrated from rest to http namespace, updated response patterns

Files not reviewed (1)

• src/Umbraco.Web.UI.Client/package-lock.json: Language not supported

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[iOvergaard]

This LGTM from the outlook I have and testing a bit here and there. It's too much to test the whole static preview, so I think the best course of action is to merge it in and see what happens.