Desktop installer: taller default window so the log has room

Start at 900 px height (min 720), both capped to the screen's working area.

desktop/OmniNX.DesktopInstaller/MainForm.cs

@@ -37,8 +37,10 @@ public sealed class MainForm : Form
     public MainForm()
     {
         Text = "OmniNX Desktop Installer";
-        MinimumSize = new Size(820, 640);
-        Size = new Size(900, 700);
+        // Tall enough that the log box has room at startup, but never taller than the screen.
+        var workArea = Screen.PrimaryScreen?.WorkingArea ?? new Rectangle(0, 0, 1280, 800);
+        MinimumSize = new Size(Math.Min(820, workArea.Width), Math.Min(720, workArea.Height));
+        Size = new Size(Math.Min(900, workArea.Width), Math.Min(900, workArea.Height));
         StartPosition = FormStartPosition.CenterScreen;
         Font = new Font("Segoe UI", 9F);
         Icon = LoadFormIcon() ?? Icon.ExtractAssociatedIcon(Application.ExecutablePath);