Replacing the main menu dropped the Edit menu that AppKit routes
Cmd+V/C/A/Z through, so the composer could not paste at all. The menu is
rebuilt with those items, which --diag now dumps so the wiring can be
checked without a keyboard.
Workspaces also gained an order: the Cmd+K switcher has up/down controls,
creating one opens a naming modal instead of prefilling the composer, and
the UI now says workspace throughout. The stored JSON keeps the original
`sections` keys so existing data and sync payloads stay valid.