* feat: integrate main layout, toolbar, and rail from redesign into main ide-react folder
* feat: remove additional files no longer used after ide redesign
GitOrigin-RevId: 8fd77f63cb9c67be91995a9dde13b0fe2376d80f
* Replace placeholders with labels
* Add 'Close dialog' label to modal close button to distinguish from footer Close button
* Add and translate heading on the not found page
* Update textarea to have id matching label's for attribute
Simplify test for template description textarea
* Label PDF zoom level dropdown button
* Improve test selectors to use semantic roles and accessible names
GitOrigin-RevId: d215ddca30ddf844cfffbcf0e528a601b134d772