Profiles: named layouts that open apps

A profile is a named layout plus the screens it hides and its apps' windows
(docs/profiles.md). ft-layout save captures them (ft-floatd's "windows",
after the KWin script reports every window as it is now); use opens them:
the screens move, open windows of each app go to their places (on a screen,
maximized or not, or floating), and missing apps start, once and then again
for each window still missing 3 s after the first. Nothing closes.

The desktop starts in FT_PROFILE or default_profile (ft-layout start, from
the session script). Each profile gets a launcher entry (Frametop: NAME, in
SteamVR's Launch a program list) that switches to it or starts the desktop
in it. The relay's profile:NAME action and Input Settings' "Open profile"
entries put one on a key, mouse button, or controller button. Display
Settings' Layout page becomes Layout & profiles: Save as profile, Open
profile, the profile's apps, and Start in profile. Plasma's own session
restore is off in the Frametop session.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -52,7 +52,8 @@ If you work in the desktop for long stretches, or leave the headset on a stand,
 | Drag the roll button sideways, or scroll on it | Rolls the screen; it snaps level near straight |
 | While carrying a screen, sweep its laser across your other controller's ring, then let go | Pins it to that wrist, at its size and distance, as you hold it when you let go; it shows while you see its front. Grab its bar to adjust it (it stays pinned); sweep across the ring again to take it off |
 | Set a screen to On your head (Frametop Display Settings, Visibility & pins) | Pins it to your head where it is, like a HUD. Grab its bar to move it; it stays on your head |
-| Save current arrangement… (Frametop Display Settings, Layout) | Saves where the screens are, with their sizes and pins, under a name. Pick a saved layout under Arrangement and press Arrange now to switch to it |
+| Save as profile… (Frametop Display Settings, Layout & profiles) | Saves where the screens are, with their sizes and pins, which ones are hidden, and the open apps and where their windows are (on a screen or floating), under a name. Pick it under Arrangement and press Open profile to switch to it: the screens move, open windows of its apps go to their places, and the apps that aren't open start. Nothing closes |
+| Pick a profile under Start in profile, or run its entry (Frametop: NAME) from SteamVR's Launch a program list | The desktop starts in that profile, or switches to it if it's running. A profile can also go on a key combination, mouse button, or controller button in Frametop Input Settings |
 | Meta+Shift+R in the desktop | Puts the screens back in their layout (also in the menu as Reset Screen Layout, and mappable to a mouse button) |
 | Meta+Shift+F over a desktop window | Floats that window in VR as a panel of its own, or puts it back on its screen if it floats. It acts on the window under the pointer, or the active one if the pointer is over the wallpaper. Rebind it, or map it to a mouse or controller button, in Frametop Input Settings (Keyboard page, or Buttons and Controllers as Float window in VR). Float in VR is also in every window's menu (Alt+F3), and the button left of Close in a window's title bar does the same (apps that draw their own title bar, like Chromium and Electron apps, don't have it) |
 | Right-click an app in the Application Launcher (or the taskbar) and pick Launch as Standalone | Starts the app with its window floating in VR, where that app last floated, or in front of you the first time. From a terminal: `float/ft-float launch org.kde.dolphin`, or `float/ft-float run <command>` |