FX.107 SuperCad: Teams and Team members are pages of the welcome area, not modal dialogs

A plugin can now register a PAGE (api.page / api.openPage; host.pages()) that the welcome screen shows with its own left-menu entry. Teams (menu entry) and Team members (reached from a team) are pages: no dialog, adding a team no longer drops you into the drawing space, and the Workflow buttons on the welcome page no longer leave it. The commands Teams, Team members and New team open the pages (New team puts the cursor in the name field). Tests tools/super-test/home-teams.mjs, bin/test-super-teams.mjs.