Bridge

@basmilius/desktop-shell/bridge holds the shapes that cross IPC between the shell and its page. It imports nothing from Electron, so a preload and the page import it as well as the main process. A preload hands every answer to the page as unknown; one shape in one place keeps both ends from drifting apart without the compiler saying so.

Name	What it is
MenuSpec, MenuNode, MENU_ROLES, MenuRole	The application menu the page builds.
UpdateState	Where updating stands.
compareVersions, isVersion	One ordering of versions for the shell and the page, so release notes land under the right heading. A version that is not a plain 1.2.3 sorts below every one that is.