FX.106 SuperCad panel tabs: the pop-out icon is replaced by the apps' "…" menu (move, show on its own, float, new window, hide)

Each panel tab, docked or floating, had a small pop-out icon that only tore the panel off. It now has the same "…" button the apps' panel grips have (app-workspace-popout.js menuButton), with Move to the left / middle / right / bottom (not the side it is on), Show on its own, Float in this window, Open in a new window (a real OS window), Hide this panel, and Put it back in the window for a floating one. Test tools/super-test/tab-menu.mjs.