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/UIGrid.cpp

@@ -3,6 +3,7 @@
 #include "McRFPy_API.h"
 #include "PyPositionHelper.h"
 #include <algorithm>
+#include "UIDrawable_methods.h"
 
 UIGrid::UIGrid() 
 : grid_x(0), grid_y(0), zoom(1.0f), center_x(0.0f), center_y(0.0f), ptex(nullptr)
@@ -602,6 +603,15 @@ PyMethodDef UIGrid::methods[] = {
     {NULL, NULL, 0, NULL}
 };
 
+// Define the PyObjectType alias for the macros
+typedef PyUIGridObject PyObjectType;
+
+// Combined methods array
+PyMethodDef UIGrid_all_methods[] = {
+    UIDRAWABLE_METHODS,
+    {"at", (PyCFunction)UIGrid::py_at, METH_VARARGS | METH_KEYWORDS},
+    {NULL}  // Sentinel
+};
 
 PyGetSetDef UIGrid::getsetters[] = {
 
@@ -627,6 +637,7 @@ PyGetSetDef UIGrid::getsetters[] = {
 
     {"texture", (getter)UIGrid::get_texture, NULL, "Texture of the grid", NULL}, //TODO 7DRL-day2-item5
     {"z_index", (getter)UIDrawable::get_int, (setter)UIDrawable::set_int, "Z-order for rendering (lower values rendered first)", (void*)PyObjectsEnum::UIGRID},
+    UIDRAWABLE_GETSETTERS,
     {NULL}  /* Sentinel */
 };