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>

float/ft-float

@@ -6,10 +6,14 @@
                                active one), or put it back if it floats
   ft-float dock [ID|active]    put a floating window back on the desktop
   ft-float dock all            put every floating window back
+  ft-float launch APP          start an app (its desktop file name, e.g. org.kde.dolphin) and
+                               float its first window where that app last floated
+  ft-float run COMMAND [ARG...]  the same for a command
   ft-float close ID            close a window
   ft-float list                the spare outputs and what floats on them
 FT_FLOAT_SOCKET names ft-floatd's socket (default frametop_float).
 """
+import json
 import os
 import socket
 import sys
@@ -20,7 +24,8 @@ s = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
 s.bind("")
 s.settimeout(5)
 try:
-    s.sendto(" ".join(sys.argv[1:]).encode(), "\0" + os.environ.get("FT_FLOAT_SOCKET", "frametop_float"))
+    text = "run " + json.dumps(sys.argv[2:]) if sys.argv[1] == "run" else " ".join(sys.argv[1:])
+    s.sendto(text.encode(), "\0" + os.environ.get("FT_FLOAT_SOCKET", "frametop_float"))
     reply = s.recv(8192).decode()
 except OSError as e:
     sys.exit(f"ft-floatd didn't answer ({e}); is the Frametop desktop running?")