Resolved an issue where items could not be added to the tracker due to the use of an incorrect ID. This caused `parseTrackResponse()` to fail in locating the 'included' key within `jsonResponse`, leading to a null return. As a result, an exception was thrown in `tracker_widget.dart` at line 134 when accessing `widget.trackRes.title!,` triggering a _TypeError (Null check operator used on a null value)_.
- Resolved the same timestamp conversion issue that affected MyAnimeList.
- Previously, seconds-to-milliseconds conversion and `DateTime.now()` were applied twice — once on `login()` and once in `_getAccessToken()` — resulting in incorrect expiry dates (e.g., year 57349).
- Updated Kitsu’s URL from `.io` to `.app`.