* Defer script loading
* Refactor loading
* Wait for project:joined
* Only mount IdePage once everything has connected
* Add useConnectionState hook and comments
* Remove placeholder components
* Move props into EditorAndSidebar
* Move props into MainLayout
* Tidy editor and sidebar components
* Lazy-load the symbol palette pane and separate the loading pane
GitOrigin-RevId: 4b721a06d6aba0ae0ec91768e6a6e29cf15e2083
