Fix menu buttons never rendering: reset canvas transform per repaint

The RcoRenderer applied translate/scale to the shared GraphicsContext on
every render, so repeated repaints (menu animations fire many) compounded
the scale and pushed the buttons off-screen. Reset the transform each
render. Also decompress zlib/RLZ RCO images (previously returned raw).

ui/src/main/java/dev/quoije/umd/ui/RcoRenderer.java

@@ -94,6 +94,9 @@ public final class RcoRenderer implements Display {
         GraphicsContext g = canvas.getGraphicsContext2D();
         double w = canvas.getWidth();
         double h = canvas.getHeight();
+
+        // Reset the transform so repeated repaints do not accumulate scale.
+        g.setTransform(1.0, 0.0, 0.0, 1.0, 0.0, 0.0);
         g.clearRect(0, 0, w, h);
 
         // RCO content is authored for the PSP movie player framebuffer, which