UI.3 Multi-monitor: any number of windows, remembered per app and layout, restored in one click

Owner: "one of our biggest desires is to be multi monitor capable". Today the panels window is one window for both panels (app-panels.js), each torn-off block is one more pop-up, and only the panels window remembers its position and screen (cc-app-settings:<slug> panels.wins, Window Management API "Put it on my other screen" in Chromium); a block's pop-up opens at a default size at the pointer's screen and is forgotten on reload; a browser cannot reopen windows without a click, so after a reload the shell can only offer "Open it". Change, on the one window service (UI.2): each window keeps {screen, x, y, w, h, contents} under cc-windows:<slug>:<layout>, the left and right panels may be two windows, a palette may leave its panel for a window of its own, several bars may share one window (a tool strip window), and on start the status line offers "Restore my 3 windows" (one click opens them all, the browser allows that inside one click), with getScreenDetails() where the browser has it and the last position elsewhere. The layout file (format v2, UI.6) may say a block starts in a window ("place": "window"), so a layout made for two screens is shareable. Studio does the same through real windows (UI.4). Works on the page too: a floating palette or bar (place float) can be dragged anywhere over the drawing and is remembered the same way, so "reorganized on the page/canvas" is the same feature with the window left out.