Default window size (width and height) too small on initial startup

[nekohayo]

• I have read the README.md document
• I am using the latest version of Warehouse
• I am using the Flatpak package of Warehouse
• I have not found any other opened issues on the same topic

Describe the issue in detail

Installing this app on a computer where I had never run it before, I ran into this UX blooper from 2005.

It seems like Warehouse defaults to default-width: 921; default-height: 450; in its main window blueprint file, but since it reuses some sort of smaller empty state window, it effectively launches at 640x363 pixels by default on first run:

…so people might not discover that it is meant to be used as a full-featured three-panes UI on the desktop.

I would recommend ensuring that it launches at 1024x768 by default at least. If the window manager determines this to be too big for the screen (ex: on a phone), it will scale it down and maximize it anyway.