feat: stabilize test suite and add UIDrawable methods

- Add visible, opacity properties to all UI classes (#87, #88)
- Add get_bounds(), move(), resize() methods to UIDrawable (#89, #98)
- Create UIDrawable_methods.h with template implementations
- Fix test termination issues - all tests now exit properly
- Fix test_sprite_texture_swap.py click handler signature
- Fix test_drawable_base.py segfault in headless mode
- Convert audio objects to pointers for cleanup (OpenAL warning persists)
- Remove debug print statements from UICaption
- Special handling for UIEntity to delegate drawable methods to sprite

All test files are now "airtight" - they complete successfully,
terminate on their own, and handle edge cases properly.

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

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

src/UISprite.cpp

@@ -2,6 +2,7 @@
 #include "GameEngine.h"
 #include "PyVector.h"
 #include "PyPositionHelper.h"
+#include "UIDrawable_methods.h"
 
 UIDrawable* UISprite::click_at(sf::Vector2f point)
 {
@@ -267,6 +268,15 @@ int UISprite::set_pos(PyUISpriteObject* self, PyObject* value, void* closure)
     return 0;
 }
 
+// Define the PyObjectType alias for the macros
+typedef PyUISpriteObject PyObjectType;
+
+// Method definitions
+PyMethodDef UISprite_methods[] = {
+    UIDRAWABLE_METHODS,
+    {NULL}  // Sentinel
+};
+
 PyGetSetDef UISprite::getsetters[] = {
     {"x", (getter)UISprite::get_float_member, (setter)UISprite::set_float_member, "X coordinate of top-left corner",   (void*)0},
     {"y", (getter)UISprite::get_float_member, (setter)UISprite::set_float_member, "Y coordinate of top-left corner",   (void*)1},
@@ -279,6 +289,7 @@ PyGetSetDef UISprite::getsetters[] = {
     {"click", (getter)UIDrawable::get_click, (setter)UIDrawable::set_click, "Object called with (x, y, button) when clicked", (void*)PyObjectsEnum::UISPRITE},
     {"z_index", (getter)UIDrawable::get_int, (setter)UIDrawable::set_int, "Z-order for rendering (lower values rendered first)", (void*)PyObjectsEnum::UISPRITE},
     {"pos", (getter)UISprite::get_pos, (setter)UISprite::set_pos, "Position as a Vector", NULL},
+    UIDRAWABLE_GETSETTERS,
     {NULL}
 };