feat(media): add Jellyfin Quick Connect and harden remote connections

Add cancellable Quick Connect pairing and shared connection guards for Jellyfin and Subsonic. Bound connection attempts, validate library access before saving credentials, and report per-provider connection and synchronization status.

cx

crates/qbz-subsonic/src/lib.rs

@@ -549,6 +549,7 @@ pub fn normalize_base_url(input: &str) -> String {
 
 fn client() -> Result<reqwest::Client> {
     reqwest::Client::builder()
+        .connect_timeout(Duration::from_secs(5))
         .timeout(HTTP_TIMEOUT)
         .build()
         .map_err(|e| transport_error(&e))