fix: Activate event window creation awaits app ready state

[dcalhoun]

Fixes https://github.com/Automattic/dotcom-forge/issues/7158.

Proposed Changes

Await the app "ready" state before creating a window within the app "activate"
event handler.

Testing Instructions

Note

The test instructions are a contrived example as the original crash is the result of a race condition between the ready and activate event handler logic. The instructions rely upon intentionally creating a window within the will-finish-launching event handler, which is guaranteed to run before the ready event.

Contrived error diff

diff --git a/src/index.ts b/src/index.ts
index 692138e..95272a7 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -246,7 +246,7 @@ async function appBoot() {
 		stopAllServersOnQuit();
 	} );
 
-	app.on( 'activate', () => {
+	app.on( 'will-finish-launching', () => {
 		// On OS X it's common to re-create a window in the app when the
 		// dock icon is clicked and there are no other windows open.
 		if ( BrowserWindow.getAllWindows().length === 0 ) {

Example window error

1. Check out the trunk branch.
2. Apply the provided diff (see above).
3. Launch the app with npm start.
4. Note the app launches with an error.
5. Check out the proposed changes.
6. Repeat steps 2-3.
7. Verify the app launches without an error.

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[derekblank]

I was able to follow the testing steps successfully:

• Observed the error on trunk, reproduced with the provided diff
• Observed the error was not present on this PR branch with the diff still applied

LGTM. Thanks for adding tests as well. 🚀

[wojtekn]

Looks good. Thanks for adding tests!