Custom Tools DX + screenshot example (#2198)

This PR adds a custom tool example, the `Screenshot Tool`.

It demonstrates how a user can create a custom tool together with custom
tool UI.

### Change Type

- [x] `minor` — New feature

### Test Plan

1. Use the screenshot example

### Release Notes

- adds ScreenshotTool custom tool example
- improvements and new exports related to copying and exporting images /
files
- loosens up types around icons and translations
- moving `StateNode.isActive` into an atom
- adding `Editor.path`

apps/vscode/editor/src/app.tsx

@@ -58,6 +58,7 @@ const menuOverrides = {
 		schema.forEach((item) => {
 			if (item.id === 'menu' && item.type === 'group') {
 				item.children = item.children.filter((menuItem) => {
+					if (!menuItem) return false
 					if (menuItem.id === 'file' && menuItem.type === 'submenu') {
 						return false
 					}