Upgrade to support API v4

### Is Your Feature Request Related to a Problem? [Lemmy issue](https://github.com/LemmyNet/lemmy/issues/5508) We just published the [first beta version of Lemmy 1.0](https://join-lemmy.org/news/2026-05-19_-_Open_beta_testing_for_Lemmy_1.0.0). It includes a new API v4 with many new features and some breaking changes. Now is the time for you to update your app and make it compatible with 1.0. For this you can follow the [upgrade guide](https://join-lemmy.org/docs/contributors/09-api-v4.html). The beta phase is also the ideal time to give feedback, and to make improvements to the API before the final 1.0 release. By the way you may also be interested in the new [plugin system](https://github.com/LemmyNet/lemmy-plugins/). ### Feature Description See above ### Alternative Solutions _No response_ ### Additional Context _No response_