🆕 Add window size persistence, exit codes, and screen size detection

screen_other.go

@@ -0,0 +1,10 @@
+//go:build !darwin
+
+package main
+
+// desktopSize is a no-op fallback on non-darwin platforms where we don't have
+// a CGo-free way to query the screen. Returns (0, 0) so the caller skips
+// clamping and uses the saved/default size as-is.
+func desktopSize() (float32, float32) {
+	return 0, 0
+}