feat(Grid): add customizable background_color property (#50)

- Added sf::Color background_color member with default dark gray
- Python property getter/setter for background_color
- Animation support for individual color components (r/g/b/a)
- Replaces hardcoded clear color in render method
- Test demonstrates color changes and property access

Closes #50

src/UIGrid.cpp

@@ -6,7 +6,8 @@
 // UIDrawable methods now in UIBase.h
 
 UIGrid::UIGrid() 
-: grid_x(0), grid_y(0), zoom(1.0f), center_x(0.0f), center_y(0.0f), ptex(nullptr)
+: grid_x(0), grid_y(0), zoom(1.0f), center_x(0.0f), center_y(0.0f), ptex(nullptr),
+  background_color(8, 8, 8, 255)  // Default dark gray background
 {
     // Initialize entities list
     entities = std::make_shared<std::list<std::shared_ptr<UIEntity>>>();
@@ -30,7 +31,8 @@ UIGrid::UIGrid()
 UIGrid::UIGrid(int gx, int gy, std::shared_ptr<PyTexture> _ptex, sf::Vector2f _xy, sf::Vector2f _wh)
 : grid_x(gx), grid_y(gy),
   zoom(1.0f), 
-  ptex(_ptex), points(gx * gy)
+  ptex(_ptex), points(gx * gy),
+  background_color(8, 8, 8, 255)  // Default dark gray background
 {
     // Use texture dimensions if available, otherwise use defaults
     int cell_width = _ptex ? _ptex->sprite_width : DEFAULT_CELL_WIDTH;
@@ -76,7 +78,7 @@ void UIGrid::render(sf::Vector2f offset, sf::RenderTarget& target)
     output.setTextureRect(
          sf::IntRect(0, 0,
          box.getSize().x, box.getSize().y));
-    renderTexture.clear(sf::Color(8, 8, 8, 255)); // TODO - UIGrid needs a "background color" field
+    renderTexture.clear(background_color);
     
     // Get cell dimensions - use texture if available, otherwise defaults
     int cell_width = ptex ? ptex->sprite_width : DEFAULT_CELL_WIDTH;
@@ -649,6 +651,29 @@ PyObject* UIGrid::py_at(PyUIGridObject* self, PyObject* args, PyObject* kwds)
     return (PyObject*)obj;
 }
 
+PyObject* UIGrid::get_background_color(PyUIGridObject* self, void* closure)
+{
+    auto& color = self->data->background_color;
+    auto type = (PyTypeObject*)PyObject_GetAttrString(McRFPy_API::mcrf_module, "Color");
+    PyObject* args = Py_BuildValue("(iiii)", color.r, color.g, color.b, color.a);
+    PyObject* obj = PyObject_CallObject((PyObject*)type, args);
+    Py_DECREF(args);
+    Py_DECREF(type);
+    return obj;
+}
+
+int UIGrid::set_background_color(PyUIGridObject* self, PyObject* value, void* closure)
+{
+    if (!PyObject_IsInstance(value, PyObject_GetAttrString(McRFPy_API::mcrf_module, "Color"))) {
+        PyErr_SetString(PyExc_TypeError, "background_color must be a Color object");
+        return -1;
+    }
+    
+    PyColorObject* color = (PyColorObject*)value;
+    self->data->background_color = color->data;
+    return 0;
+}
+
 PyMethodDef UIGrid::methods[] = {
     {"at", (PyCFunction)UIGrid::py_at, METH_VARARGS | METH_KEYWORDS},
     {NULL, NULL, 0, NULL}
@@ -687,6 +712,7 @@ PyGetSetDef UIGrid::getsetters[] = {
     {"click", (getter)UIDrawable::get_click, (setter)UIDrawable::set_click, "Object called with (x, y, button) when clicked", (void*)PyObjectsEnum::UIGRID},
 
     {"texture", (getter)UIGrid::get_texture, NULL, "Texture of the grid", NULL}, //TODO 7DRL-day2-item5
+    {"background_color", (getter)UIGrid::get_background_color, (setter)UIGrid::set_background_color, "Background color of the grid", NULL},
     {"z_index", (getter)UIDrawable::get_int, (setter)UIDrawable::set_int, "Z-order for rendering (lower values rendered first)", (void*)PyObjectsEnum::UIGRID},
     {"name", (getter)UIDrawable::get_name, (setter)UIDrawable::set_name, "Name for finding elements", (void*)PyObjectsEnum::UIGRID},
     UIDRAWABLE_GETSETTERS,
@@ -1455,6 +1481,22 @@ bool UIGrid::setProperty(const std::string& name, float value) {
         z_index = static_cast<int>(value);
         return true;
     }
+    else if (name == "background_color.r") {
+        background_color.r = static_cast<uint8_t>(std::max(0.0f, std::min(255.0f, value)));
+        return true;
+    }
+    else if (name == "background_color.g") {
+        background_color.g = static_cast<uint8_t>(std::max(0.0f, std::min(255.0f, value)));
+        return true;
+    }
+    else if (name == "background_color.b") {
+        background_color.b = static_cast<uint8_t>(std::max(0.0f, std::min(255.0f, value)));
+        return true;
+    }
+    else if (name == "background_color.a") {
+        background_color.a = static_cast<uint8_t>(std::max(0.0f, std::min(255.0f, value)));
+        return true;
+    }
     return false;
 }
 
@@ -1510,6 +1552,22 @@ bool UIGrid::getProperty(const std::string& name, float& value) const {
         value = static_cast<float>(z_index);
         return true;
     }
+    else if (name == "background_color.r") {
+        value = static_cast<float>(background_color.r);
+        return true;
+    }
+    else if (name == "background_color.g") {
+        value = static_cast<float>(background_color.g);
+        return true;
+    }
+    else if (name == "background_color.b") {
+        value = static_cast<float>(background_color.b);
+        return true;
+    }
+    else if (name == "background_color.a") {
+        value = static_cast<float>(background_color.a);
+        return true;
+    }
     return false;
 }