Hides a route's tab for good (a page the build does not carry); the host decides what its page shows instead.
Adds a tab and a page for each module panel. Call before start.
Shows the page the hash names (toggling pages and tabs, running controllers).
Navigation targets for the (non-workspace) panels mounted so far.
Sets up theme, the service worker, the shortcut sheet, key bindings, hash routing and the Developer switch.
Optionaloptions: ShellStartRecomputes the tab row's scroll-edge fades.
Page controllers by route id; hosts fill it before the first navigation.