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/UIEntity.cpp

@@ -5,6 +5,7 @@
 #include "PyObjectUtils.h"
 #include "PyVector.h"
 #include "PyPositionHelper.h"
+#include "UIDrawable_methods.h"
 
 
 UIEntity::UIEntity() 
@@ -362,6 +363,18 @@ PyMethodDef UIEntity::methods[] = {
     {NULL, NULL, 0, NULL}
 };
 
+// Define the PyObjectType alias for the macros
+typedef PyUIEntityObject PyObjectType;
+
+// Combine base methods with entity-specific methods
+PyMethodDef UIEntity_all_methods[] = {
+    UIDRAWABLE_METHODS,
+    {"at", (PyCFunction)UIEntity::at, METH_O},
+    {"index", (PyCFunction)UIEntity::index, METH_NOARGS, "Return the index of this entity in its grid's entity collection"},
+    {"die", (PyCFunction)UIEntity::die, METH_NOARGS, "Remove this entity from its grid"},
+    {NULL}  // Sentinel
+};
+
 PyGetSetDef UIEntity::getsetters[] = {
     {"draw_pos", (getter)UIEntity::get_position, (setter)UIEntity::set_position, "Entity position (graphically)", (void*)0},
     {"pos", (getter)UIEntity::get_position, (setter)UIEntity::set_position, "Entity position (integer grid coordinates)", (void*)1},
@@ -370,6 +383,7 @@ PyGetSetDef UIEntity::getsetters[] = {
     {"sprite_number", (getter)UIEntity::get_spritenumber, (setter)UIEntity::set_spritenumber, "Sprite index on the texture on the display (deprecated: use sprite_index)", NULL},
     {"x", (getter)UIEntity::get_float_member, (setter)UIEntity::set_float_member, "Entity x position", (void*)0},
     {"y", (getter)UIEntity::get_float_member, (setter)UIEntity::set_float_member, "Entity y position", (void*)1},
+    UIDRAWABLE_GETSETTERS,
     {NULL}  /* Sentinel */
 };