When appearance mode was toggled between dark and light with default
settings, PhotoCraft switched from Pro Medium (Pro layout) to Studio Light
(Studio layout), altering the UI and displaying a Fit button in the status
bar.
Now that the Photoshop Pro light brightness levels exist (#2661), default
the saved light theme to Pro Light so the Pro interface layout and status
bar are preserved when toggling appearance. Also map the "light" alias to
Pro Light and list the Pro options first under Light Theme preferences.
Fixes#5016.