Remove mcrfpy.Animation from public Python module exports

Move PyAnimationType from exported_types[] to internal_types[] in
McRFPy_API.cpp. The C++ Animation class continues to exist; it is
constructed internally by drawable.animate(...) via std::make_shared
and wrapped via tp_alloc against the (still PyType_Ready'd) type.

Direct construction via mcrfpy.Animation(...) is removed because every
Animation is bound to a target object, which is more naturally
expressed as obj.animate(...). Pre-1.0 API freeze, no compat shim.

Tests using mcrfpy.Animation(...) will need to be updated separately.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/McRFPy_API.cpp

@@ -497,9 +497,6 @@ PyObject* PyInit_mcrfpy()
         /*grid layers (#147)*/
         &PyColorLayerType, &PyTileLayerType,
 
-        /*animation*/
-        &PyAnimationType,
-
         /*timer*/
         &PyTimerType,
 
@@ -574,6 +571,10 @@ PyObject* PyInit_mcrfpy()
         /*shader uniform collection - returned by drawable.uniforms but not directly instantiable (#106)*/
         &mcrfpydef::PyUniformCollectionType,
 
+        /*animation - constructed internally by drawable.animate() and returned by mcrfpy.animations,
+          but not directly instantiable from Python (pre-1.0 API freeze)*/
+        &PyAnimationType,
+
         nullptr};
     
     // Set up PyWindowType methods and getsetters before PyType_Ready