feat: Add Entity.die() method for lifecycle management closes #30

- Remove entity from its grid's entity list
- Clear grid reference after removal
- Safe to call multiple times (no-op if not on grid)
- Works with shared_ptr entity management

src/UIEntity.cpp

@@ -1,6 +1,7 @@
 #include "UIEntity.h"
 #include "UIGrid.h"
 #include "McRFPy_API.h"
+#include <algorithm>
 #include "PyObjectUtils.h"
 #include "PyVector.h"
 
@@ -323,9 +324,36 @@ int UIEntity::set_float_member(PyUIEntityObject* self, PyObject* value, void* cl
     return 0;
 }
 
+PyObject* UIEntity::die(PyUIEntityObject* self, PyObject* Py_UNUSED(ignored))
+{
+    // Check if entity has a grid
+    if (!self->data || !self->data->grid) {
+        Py_RETURN_NONE;  // Entity not on a grid, nothing to do
+    }
+    
+    // Remove entity from grid's entity list
+    auto grid = self->data->grid;
+    auto& entities = grid->entities;
+    
+    // Find and remove this entity from the list
+    auto it = std::find_if(entities->begin(), entities->end(),
+        [self](const std::shared_ptr<UIEntity>& e) {
+            return e.get() == self->data.get();
+        });
+    
+    if (it != entities->end()) {
+        entities->erase(it);
+        // Clear the grid reference
+        self->data->grid.reset();
+    }
+    
+    Py_RETURN_NONE;
+}
+
 PyMethodDef UIEntity::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, NULL, 0, NULL}
 };