os_gfx -> report mouse move events; still allow passive mouse interaction if window is unfocused, but have recently received mousemove events

src/os/gfx/os_gfx.h

@@ -40,6 +40,7 @@ typedef enum OS_EventKind
   OS_EventKind_Null,
   OS_EventKind_Press,
   OS_EventKind_Release,
+  OS_EventKind_MouseMove,
   OS_EventKind_Text,
   OS_EventKind_Scroll,
   OS_EventKind_WindowLoseFocus,

src/os/gfx/win32/os_gfx_win32.c

@@ -429,6 +429,13 @@ w32_wnd_proc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
         }
       }break;
       
+      case WM_MOUSEMOVE:
+      {
+        OS_Event *event = w32_push_event(OS_EventKind_MouseMove, window);
+        event->pos.x = (F32)LOWORD(lParam);
+        event->pos.y = (F32)HIWORD(lParam);
+      }break;
+      
       case WM_MOUSEWHEEL:
       {
         S16 wheel_delta = HIWORD(wParam);