use native structuredClone on node, cloudflare workers, and in tests (#3166)

Currently, we only use native `structuredClone` in the browser, falling
back to `JSON.parse(JSON.stringify(...))` elsewhere, despite Node
supporting `structuredClone` [since
v17](https://developer.mozilla.org/en-US/docs/Web/API/structuredClone)
and Cloudflare Workers supporting it [since
2022](https://blog.cloudflare.com/standards-compliant-workers-api/).
This PR adjusts our shim to use the native `structuredClone` on all
platforms, if available.

Additionally, `jsdom` doesn't implement `structuredClone`, a bug [open
since 2022](https://github.com/jsdom/jsdom/issues/3363). This PR patches
`jsdom` environment in all packages/apps that use it for tests.

Also includes a driveby removal of `deepCopy`, a function that is
strictly inferior to `structuredClone`.

### Change Type

<!-- ❗ Please select a 'Scope' label ❗️ -->

- [x] `sdk` — Changes the tldraw SDK
- [x] `dotcom` — Changes the tldraw.com web app
- [ ] `docs` — Changes to the documentation, examples, or templates.
- [ ] `vs code` — Changes to the vscode plugin
- [ ] `internal` — Does not affect user-facing stuff

<!-- ❗ Please select a 'Type' label ❗️ -->

- [ ] `bugfix` — Bug fix
- [ ] `feature` — New feature
- [x] `improvement` — Improving existing features
- [x] `chore` — Updating dependencies, other boring stuff
- [ ] `galaxy brain` — Architectural changes
- [ ] `tests` — Changes to any test code
- [ ] `tools` — Changes to infrastructure, CI, internal scripts,
debugging tools, etc.
- [ ] `dunno` — I don't know


### Test Plan

1. A smoke test would be enough

- [ ] Unit Tests
- [x] End to end tests

scripts/prepack.ts

@@ -23,6 +23,7 @@ export async function preparePackage({ sourcePackageDir }: { sourcePackageDir: s
 	const cssFiles = glob.sync(path.join(sourcePackageDir, '*.css'))
 
 	// construct the final package.json
+	// eslint-disable-next-line no-restricted-globals
 	const newManifest = structuredClone({
 		// filter out comments
 		...Object.fromEntries(