feat(Python): establish proper inheritance hierarchy for UI types

All UIDrawable-derived Python types now properly inherit from the Drawable
base class in Python, matching the C++ inheritance structure.

Changes:
- Add Py_TPFLAGS_BASETYPE to PyDrawableType to allow inheritance
- Set tp_base = &mcrfpydef::PyDrawableType for all UI types
- Add PyDrawable.h include to UI type headers
- Rename _Drawable to Drawable and update error message

This enables proper Python inheritance: Frame, Caption, Sprite, Grid,
and Entity all inherit from Drawable, allowing shared functionality
and isinstance() checks.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/PyDrawable.cpp

@@ -154,14 +154,14 @@ static PyMethodDef PyDrawable_methods[] = {
 // Type initialization
 static int PyDrawable_init(PyDrawableObject* self, PyObject* args, PyObject* kwds)
 {
-    PyErr_SetString(PyExc_TypeError, "_Drawable is an abstract base class and cannot be instantiated directly");
+    PyErr_SetString(PyExc_TypeError, "Drawable is an abstract base class and cannot be instantiated directly");
     return -1;
 }
 
 namespace mcrfpydef {
     PyTypeObject PyDrawableType = {
         .ob_base = {.ob_base = {.ob_refcnt = 1, .ob_type = NULL}, .ob_size = 0},
-        .tp_name = "mcrfpy._Drawable",
+        .tp_name = "mcrfpy.Drawable",
         .tp_basicsize = sizeof(PyDrawableObject),
         .tp_itemsize = 0,
         .tp_dealloc = (destructor)[](PyObject* self) {
@@ -169,7 +169,7 @@ namespace mcrfpydef {
             obj->data.reset();
             Py_TYPE(self)->tp_free(self);
         },
-        .tp_flags = Py_TPFLAGS_DEFAULT, // | Py_TPFLAGS_BASETYPE,
+        .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
         .tp_doc = PyDoc_STR("Base class for all drawable UI elements"),
         .tp_methods = PyDrawable_methods,
         .tp_getset = PyDrawable_getsetters,

src/UICaption.h

@@ -2,6 +2,7 @@
 #include "Common.h"
 #include "Python.h"
 #include "UIDrawable.h"
+#include "PyDrawable.h"
 
 class UICaption: public UIDrawable
 {
@@ -68,7 +69,7 @@ namespace mcrfpydef {
         .tp_methods = UICaption_methods,
         //.tp_members = PyUIFrame_members,
         .tp_getset = UICaption::getsetters,
-        //.tp_base = NULL,
+        .tp_base = &mcrfpydef::PyDrawableType,
         .tp_init = (initproc)UICaption::init,
         // TODO - move tp_new to .cpp file as a static function (UICaption::new)
         .tp_new = [](PyTypeObject* type, PyObject* args, PyObject* kwds) -> PyObject*

src/UIEntity.h

@@ -8,6 +8,7 @@
 
 #include "PyCallable.h"
 #include "PyTexture.h"
+#include "PyDrawable.h"
 #include "PyColor.h"
 #include "PyVector.h"
 #include "PyFont.h"
@@ -86,6 +87,7 @@ namespace mcrfpydef {
         .tp_doc = "UIEntity objects",
         .tp_methods = UIEntity_all_methods,
         .tp_getset = UIEntity::getsetters,
+        .tp_base = &mcrfpydef::PyDrawableType,
         .tp_init = (initproc)UIEntity::init,
         .tp_new = PyType_GenericNew,
     };

src/UIFrame.h

@@ -8,6 +8,7 @@
 
 #include "PyCallable.h"
 #include "PyColor.h"
+#include "PyDrawable.h"
 #include "PyVector.h"
 #include "UIDrawable.h"
 #include "UIBase.h"
@@ -89,7 +90,7 @@ namespace mcrfpydef {
         .tp_methods = UIFrame_methods,
         //.tp_members = PyUIFrame_members,
         .tp_getset = UIFrame::getsetters,
-        //.tp_base = NULL,
+        .tp_base = &mcrfpydef::PyDrawableType,
         .tp_init = (initproc)UIFrame::init,
         .tp_new = [](PyTypeObject* type, PyObject* args, PyObject* kwds) -> PyObject*
         {

src/UIGrid.h

@@ -8,6 +8,7 @@
 
 #include "PyCallable.h"
 #include "PyTexture.h"
+#include "PyDrawable.h"
 #include "PyColor.h"
 #include "PyVector.h"
 #include "PyFont.h"
@@ -39,6 +40,7 @@ public:
     sf::FloatRect get_bounds() const override;
     void move(float dx, float dy) override;
     void resize(float w, float h) override;
+    void onPositionChanged() override;
 
     int grid_x, grid_y;
     //int grid_size; // grid sizes are implied by IndexTexture now
@@ -153,7 +155,7 @@ namespace mcrfpydef {
         .tp_methods = UIGrid_all_methods,
         //.tp_members = UIGrid::members,
         .tp_getset = UIGrid::getsetters,
-        //.tp_base = NULL,
+        .tp_base = &mcrfpydef::PyDrawableType,
         .tp_init = (initproc)UIGrid::init,
         .tp_new = [](PyTypeObject* type, PyObject* args, PyObject* kwds) -> PyObject*
         {

src/UISprite.h

@@ -8,6 +8,7 @@
 
 #include "PyCallable.h"
 #include "PyTexture.h"
+#include "PyDrawable.h"
 #include "PyColor.h"
 #include "PyVector.h"
 #include "PyFont.h"
@@ -95,7 +96,7 @@ namespace mcrfpydef {
         .tp_methods = UISprite_methods,
         //.tp_members = PyUIFrame_members,
         .tp_getset = UISprite::getsetters,
-        //.tp_base = NULL,
+        .tp_base = &mcrfpydef::PyDrawableType,
         .tp_init = (initproc)UISprite::init,
         .tp_new = [](PyTypeObject* type, PyObject* args, PyObject* kwds) -> PyObject*
         {