chore: remove dead code to eliminate all compiler warnings

- Remove unused get_artist() (replaced by get_artist_page())
- Remove unused Format::label(), Format::all()
- Remove unused QwsTokenResponse and QwsToken structs
- Remove unused PlayerCommand::Seek (seeking uses atomics directly)
- Remove unused PlayerState::Stopped, TrackInfo::format
- Remove unused PlayerStatus::get_current_track()

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

rust/src/api/models.rs

@@ -244,30 +244,5 @@ impl Format {
         }
     }
 
-    pub fn label(self) -> &'static str {
-        match self {
-            Format::Mp3 => "MP3 320",
-            Format::Cd => "CD 16-bit",
-            Format::HiRes96 => "Hi-Res 24-bit/96kHz",
-            Format::HiRes192 => "Hi-Res 24-bit/192kHz",
-        }
-    }
-
-    pub fn all() -> &'static [Format] {
-        &[Format::HiRes192, Format::HiRes96, Format::Cd, Format::Mp3]
-    }
 }
 
-// --- QWS ---
-
-#[derive(Debug, Deserialize, Clone, Serialize)]
-pub struct QwsTokenResponse {
-    pub jwt_qws: Option<QwsToken>,
-}
-
-#[derive(Debug, Deserialize, Clone, Serialize)]
-pub struct QwsToken {
-    pub exp: Option<i64>,
-    pub jwt: Option<String>,
-    pub endpoint: Option<String>,
-}