xed does not save the window position, only its size

xed restores the window size across restarts, but never the position: the window always
comes up wherever the window manager decides to put it. Moving it, closing it and reopening
loses the placement every time.

The reason looks like the position is simply never stored. The state schema only carries a
size and a state key, with nothing for the position:

$ gsettings list-keys org.x.editor.state.window
bottom-panel-active-page
bottom-panel-size
side-panel-active-page
side-panel-size
size
state

$ gsettings get org.x.editor.state.window size
(1720, 1372)

That matches the history here: #24 asked for both size and position and was closed by PR #68,
which added the size handling only. #389 reported the position part again in 2020 and was
closed without a change.

Worth noting for whoever picks this up: storing the position is necessary but not sufficient
on Cinnamon. The xed window ships no position hint —

$ xprop -id <xed window> WM_NORMAL_HINTS
WM_NORMAL_HINTS(WM_SIZE_HINTS):
        program specified minimum size: 566 by 105
        program specified base size: 0 by 0
        window gravity: NorthWest

there is no program specified location / user specified location line, i.e. neither
PPosition nor USPosition is set. Muffin skips its own placement only for windows that set one
of those flags, so a window without them gets auto-placed regardless of what the application
asked for. Calling gtk_window_move() before the window is shown sets the flag and is what the
other applications in the session (Brave, Bitwarden, PhpStorm, Double Commander) do — all of
them restore their position correctly under the same window manager.

Environment

• xed 3.8.9+zena
• Linux Mint 22.2, Cinnamon 6.6.4, Muffin 6.6.1
• X11, GTK 3.24.41, single 3440x1440 monitor

Begin by tracing xed's existing window-state handling and the startup path that restores its size; the issue identifies the org.x.editor.state.window schema as the relevant state entry point. Confirm that position is persisted and applied before the window is shown, then verify with xprop and repeated restarts under Cinnamon that placement is retained.