A float button in every window's title bar

Frametop's own window decoration (decoration/), a QML decoration for KWin's
Aurorae engine drawn like Breeze, puts a float button left of Close. It's the
Keep Below button with its own glyph: the KWin script floats a window when
keep-below is set and docks it when it's cleared, and keeps the flag set on
every floating window, so the button shows "back to the desktop" there. The
session script installs the decoration for the Frametop desktop only;
decoration/apply.sh switches a running desktop to it or back to Breeze.

Not yet tried in a running KWin.

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

docs/floating-windows.md

@@ -9,6 +9,8 @@ Built so far (2026-09-29; the KWin side tested on the headless test desktop, `sc
 - ft-screens: a panel per spare output (`frametop.float.N`) with the crop, density, popups and dialogs as small panels over it, title-bar carrying, the corner tab resizing the window, and dock and close buttons. `--spares`, and the commands `float`, `unfloat`, `pose`, `sub`, `minimized`, `carry`.
 - The session adds `FLOAT_SLOTS` spares and starts ft-floatd from the desktop's autostart; ft-layout leaves the spares alone.
 - The 3D mouse's drag lock crosses onto other Frametop panels (not while carrying one).
+- The float key (2026-09-30): the input relay's `float_toggle` (Meta+Shift+F by default) and `dock_all`, through `float pointer` and `dock all` on ft-floatd. Tested on the headless desktop.
+- The title bar button (2026-09-30, branch `float-titlebar`): `decoration/` (Frametop's QML window decoration, installed by the session script; `decoration/apply.sh` switches the running desktop to it or back to Breeze), and keep-below as the floating flag in the script. Not yet tried in a running KWin.
 
 Not built yet: phase 2 (the ghost, tear-off by dragging, push-flush docking), phase 3 (launching floating, Launch as Standalone, remembered placement), and phase 4.