fix: update ResizeObserver and IntersectionObserver mocks for vitest v4

[Copilot]

Description

Fixes test failures caused by Vitest v4's stricter constructor mock requirements.

In Vitest v4, vi.fn().mockReturnValue() doesn't work when the mock is invoked with new. The ResizeObserver and IntersectionObserver mocks were failing because they returned plain objects instead of being proper constructor functions.

Before (broken):

const mockResizeObserver = vi.fn()
mockResizeObserver.mockReturnValue({
  observe: () => null,
  unobserve: () => null,
  disconnect: () => null,
})

After (fixed):

;(globalThis as any).ResizeObserver = vi.fn(function (this: any) {
  this.observe = vi.fn()
  this.unobserve = vi.fn()
  this.disconnect = vi.fn()
})

What to review

• packages/sanity/test/setup/environment.ts - updated mock implementations

Testing

Verified locally that previously failing tests now pass (useDocumentSheetColumns, DeletedDocumentBanners, useDocumentTitle, DocumentHeaderTitle, PaneContainer).

Notes for release

Not required - internal test infrastructure change only.

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Project	Deployment	Preview	Comments	Updated (UTC)
page-building-studio	Ready	Preview	Comment	Nov 25, 2025 1:41pm
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2 Skipped Deployments

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studio-workshop	Ignored	Preview		Nov 25, 2025 1:41pm
test-next-studio	Ignored			Nov 25, 2025 1:41pm

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🔑 Environment Variables for Local Testing

This is the preview URL for the E2E tests: https://e2e-studio-qk38selvm.sanity.dev

To run the E2E tests locally, you can use the following environment variables, then run pnpm test:e2e --ui to open the Playwright test runner.

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  SANITY_E2E_PROJECT_ID=ittbm412
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  SANITY_E2E_DATASET_CHROMIUM=pr-11262-chromium-19671364346
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Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• ppsg7ml5.api.sanity.io
  • Triggering command: /usr/local/bin/node /usr/local/bin/node --conditions node --conditions development --experimental-import-meta-resolve --require /home/REDACTED/work/sanity/sanity/node_modules/.pnpm/[email protected]_@edge-runtime+[email protected]_@types+[email protected]_@types+[email protected][email protected]_612277988f9bbbcb751927ebe4afbe4e/node_modules/vitest/suppress-warnings.cjs /home/REDACTED/work/sanity/sanity/node_modules/.pnpm/[email protected]_@edge-runtime+[email protected]_@types+[email protected]_@types+[email protected][email protected]_612277988f9bbbcb751927ebe4afbe4e/node_modules/vitest/dist/workers/forks.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)