Add Android client support and unify cross-platform builds

pkg/utils/screenshot_stub.go

@@ -0,0 +1,15 @@
+//go:build !windows && !linux && !darwin
+
+package utils
+
+import "fmt"
+
+// CaptureScreenshot is not available on this platform.
+func CaptureScreenshot(quality int) ([]byte, int, int, error) {
+	return nil, 0, 0, fmt.Errorf("screenshot not supported on this platform")
+}
+
+// CaptureAllScreens is not available on this platform.
+func CaptureAllScreens(quality int) ([]byte, int, int, error) {
+	return nil, 0, 0, fmt.Errorf("screenshot not supported on this platform")
+}