feat(backlog): save only the changed fields

src/pages/GameDetail.test.jsx

@@ -116,7 +116,8 @@ describe('GameDetail', () => {
         });
 
     it('keeps unsaved notes in the backlog card when the hint sets the game to playing', async () => {
-        answer(game, {'PUT /api/library/games/220/backlog': echo});
+        // Core changes only the status and answers the whole entry.
+        answer(game, {'PUT /api/library/games/220/status': (url, init) => json(200, {...game, ...JSON.parse(init.body)})});
         renderDetail();
         const notes = await screen.findByLabelText('BACKLOG.NOTES_LABEL');
         fireEvent.change(notes, {target: {value: 'my draft'}});