Add music sharing and mobile player polish

Add track, release, and queue sharing with post-login redirects; support shared playlist links and highlighted shared tracks.

Add local synchronized playback for jams, constrain HTTP metrics to known routes, and refine mobile player controls/layout.

src/player/dto.rs

@@ -289,6 +289,19 @@ pub(super) struct PlaylistDetail {
     pub(super) tracks: Vec<TrackItem>,
 }
 
+#[derive(Debug, Serialize, JsonSchema)]
+pub(super) struct ShareLinkResponse {
+    pub(super) token: String,
+    pub(super) url: String,
+}
+
+#[derive(Debug, Serialize, JsonSchema)]
+pub(super) struct PlaylistShareDetail {
+    pub(super) token: String,
+    pub(super) title: String,
+    pub(super) tracks: Vec<TrackItem>,
+}
+
 #[derive(Debug, Serialize, JsonSchema)]
 pub(super) struct SearchResults {
     pub(super) artists: Vec<ArtistCard>,