feat(settings): store a favorite platform

readme.md

@@ -95,6 +95,7 @@ To Be Played is split into three repositories:
 | `PUT` | `/api/users/settings/appearance` | access token |
 | `PUT` | `/api/users/settings/profile-style` (`{accent, corners, bannerAppid, backgroundAppid}`; `204`) | access token |
 | `PUT` | `/api/users/settings/dashboard-tiles` (`{tiles: [{id, size}]}` in order, at most 20; `{tiles: null}` resets; `204`) | access token |
+| `PUT` | `/api/users/settings/favorite-platform` (`{platform}`, free text up to 32, e.g. `PS5`; `null` clears it; `204`) | access token |
 | `PUT` | `/api/users/settings/profile-tiles` (`{tiles: [{id, size}]}`: `SUMMARY`, `STATUS`, `PLAYING`, `FINISHED`, `STATS_<GROUP>`; `204`) | access token |
 | `GET` | `/api/public/profiles/{displayName}` | public |
 | `GET` | `/api/stats/public` | public |