Launch apps floating, remember where they floated, and Launch as Standalone

ft-float launch APP / run COMMAND: ft-floatd starts the app and floats its
first window (matched by process or desktop file name for 30 s) where that
app last floated, or in front of you at the primary screen's density. Each
app's place (pose relative to the primary screen, size in pixels, scale) is
kept in ~/.config/frametop-float.json whenever one of its windows stops
floating; the scale isn't applied yet, since rescaling can loop (written up
in docs/floating-windows.md, Known problems).

Launch as Standalone (float/ft_apps.py): the session writes copies of the
apps' desktop files with that action and puts them first in XDG_DATA_DIRS,
so it shows in the Application Launcher's and the taskbar's right-click menus
in the Frametop desktop only. ft-floatd rewrites them when apps change.

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

session/frametop-session.sh

@@ -196,6 +196,14 @@ else
   rm -f "$autostart"
 fi
 
+# Launch as Standalone in every app's right-click menu (float/ft_apps.py): copies of the
+# apps' desktop files with that action, first in XDG_DATA_DIRS, so only this desktop sees
+# them. Written now, before Plasma reads them; ft-floatd keeps them up to date.
+if [ "$float_slots" -gt 0 ]; then
+  python3 "$here/../float/ft_apps.py" >/dev/null 2>&1 || true
+  export XDG_DATA_DIRS=$HOME/.local/share/frametop/apps:${XDG_DATA_DIRS:-/usr/local/share:/usr/share}
+fi
+
 # With floating windows, the session's windows get Frametop's own decoration: Breeze's look
 # plus a float button left of Close (decoration/, a QML decoration KWin's Aurorae engine
 # loads; docs/floating-windows.md). It's copied, not linked: KPackage doesn't list linked