Summary

Fix deep link handling on cold start (app not running) for extension, session, and recipe deep links.

Also noticed deeplinks stopped launching from cold start after nextcamp.

Goose created this but I wasn't able to test cold start launch it would only launch my goose app in applications and copying to Applications wasn't getting around it so we'll need to see after the next release. Verified deeplinks still open when app is running so there should be no regression here only hopeful improvement :)

fixes #3972

Problem

When clicking a goose:// deep link while Goose is not running:

1. Extension deep links failed silently - the app launched but the extension install modal never appeared
2. Recipe deep links failed silently - the app launched but the recipe didn't run
3. Duplicate windows could be created - both the open-url handler and appMain() would create windows

Root Cause

Two issues in the open-url event handler:

1. Missing app.whenReady() call: On macOS, open-url can fire before the app is ready. The handler was calling createChat() (which creates a BrowserWindow) without waiting for the app to be ready, causing the window creation to fail silently.

2. Race condition for IPC messages: For extension/session deep links, IPC messages (add-extension, open-shared-session) were sent immediately after window creation, before React had mounted and registered its listeners. The messages were lost.

Solution

1. Added await app.whenReady() in the open-url handler before creating any windows (critical fix for cold start)
2. Added openUrlHandledLaunch flag to track when open-url has already created a window for a deep link
3. Modified open-url handler to defer IPC messages for extension/session deep links until React is ready (stored in pendingDeepLink)
4. Modified appMain() to skip window creation if openUrlHandledLaunch is true
5. Modified react-ready IPC handler to process pendingDeepLink by sending the appropriate IPC message to the now-ready window

Result

• App properly launches on cold start deep links (was silently failing before)
• Single window opens (no duplicates)
• Extension install modal appears correctly when clicking extension deep links
• Recipe deep links now work correctly on cold start
• Session sharing deep links now work on cold start