wayland: Add null check for cursor shape device (#145)

Fixes segmentation fault when running on Wayland compositors that don't support the cursor_shape_v1 protocol (e.g., Wayfire).

The crash occurs in the pointer enter event handler when attempting to call m_pCursorShapeDevice->sendSetShape() without checking if the device was successfully initialized. On compositors without cursor_shape_v1 support, m_pCursorShapeDevice remains null, leading to a null pointer dereference.

src/hyprpicker.cpp

@@ -630,6 +630,7 @@ void CHyprpicker::initMouse() {
             }
         }
 
+        if (m_pCursorShapeDevice)
             m_pCursorShapeDevice->sendSetShape(serial, WP_CURSOR_SHAPE_DEVICE_V1_SHAPE_CROSSHAIR);
 
         markDirty();