Fixed the rejected issue where QQ Music failed to play after being added. Streaming requires a direct connection to the provider's servers, which some networks block: adding the source appeared to succeed, but every action afterwards failed. The app now probes provider reachability at startup and omits unreachable providers from the add-source list (they come back after a restart once the network reaches them), so every offered entry works. The auto-login inject file is also restored (its absence made the entry return Injection Failed), and a demo track is bundled so a fresh install can play audio immediately.