Draw no cloak for "None" instead of the missing texture

"None" is the empty cloak id, but getCurrentCloakTexture still built textures/cloaks/.png from it, so
the renderer drew Minecraft's missing texture. It now returns null for an empty id and for any id
this version has no texture for, and the renderer already skips a null texture.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/main/java/org/saturnclient/cosmetics/Cloaks.java

@@ -38,7 +38,14 @@ public class Cloaks {
         availableCloaks.add(0, "");
     }
 
+    /**
+     * The cloak's texture, or null for no cloak ("", the "None" choice) and for a cloak this version
+     * has no texture for, which would otherwise draw as the missing texture.
+     */
     public static IdentifierRef getCurrentCloakTexture(String cloakName) {
+        if (cloakName == null || !Arrays.asList(ALL_CLOAKS).contains(cloakName)) {
+            return null;
+        }
         if (Arrays.asList(ANIMATED_CLOAKS).contains(cloakName)) {
             return IdentifierRef.ofSaturn("textures/cloaks/" + cloakName + ".gif");
         } else {