Sync implementation for subscriptions, tracking subscription removals, add fcast link to cast tutorial description.

Added background subscription upadte failed toast and removed home page refresh when older than a minute.

Fix channel content not showing older non-videos, fix seperated channel contents not being fetched if not both streams and videos are included

PeekChannelContent and initial algorithm support, DevSubmit support, Prevent crash url search before init, Documentation url scanning for devportal, limit ongoing downloads ui to 4

Deleting playlist video deletes local files, Post links are now clickable, going back to channel page from post now shows channel page correctly, search capabilities correct for channel content search, Fix loader not disappearing in certain cases on post details

Grayjay logo, WatchLater button, WatchLater download, Download notification dismiss fix, Polycentric open platform, Minor utility additions, Dev method documentation url support

Support for cache in reconstructions, non-required cache added to exports, playlists shares now add a cache aswell for quicker importing

Added scroll to top. Full scrollable parent comment and Polycentric process secret backup and automatic database recovery.

Refs, Dev portal improvements and on-device testing, Fix crashes on disabling v8 race conditions, edgecase where history could be null, issue on starting Grayjay with an url

Fixed crash where it would fail to unregister audio noisy receiver. Fixed crash where system brightness setting does not exist.