Add seek and volume controls

- Left/Right arrows: seek backward/forward 10 seconds
- +/- keys: adjust volume by 5% increments
- Volume clamped between 0-100%
- Only allow seeking when track is playing
- Update status bar help text with new controls

src/main.rs

@@ -177,6 +177,30 @@ async fn handle_key_event(state: &mut AppState, player: &mut player::Player, key
                 PlayerState::Stopped => {}
             }
         }
+        KeyCode::Left => {
+            if state.player_state != PlayerState::Stopped {
+                player.seek(-10.0)?;
+                tracing::info!("Seek backward 10s");
+            }
+        }
+        KeyCode::Right => {
+            if state.player_state != PlayerState::Stopped {
+                player.seek(10.0)?;
+                tracing::info!("Seek forward 10s");
+            }
+        }
+        KeyCode::Char('+') | KeyCode::Char('=') => {
+            let new_volume = (state.volume + 5).min(100);
+            state.volume = new_volume;
+            player.set_volume(new_volume)?;
+            tracing::info!("Volume: {}%", new_volume);
+        }
+        KeyCode::Char('-') => {
+            let new_volume = (state.volume - 5).max(0);
+            state.volume = new_volume;
+            player.set_volume(new_volume)?;
+            tracing::info!("Volume: {}%", new_volume);
+        }
         KeyCode::Char('r') => {
             state.is_refreshing = true;
             tracing::info!("Rescanning...");

src/ui/mod.rs

@@ -149,7 +149,7 @@ fn render_title_bar(frame: &mut Frame, state: &AppState, area: Rect) {
 }
 
 fn render_status_bar(frame: &mut Frame, _state: &AppState, area: Rect) {
-    let shortcuts = "↑↓/jk: Navigate • h/l: Fold • t: Mark • c: Clear • Enter: Play • Space: Pause • n/p: Next/Prev • r: Rescan • q: Quit";
+    let shortcuts = "↑↓/jk: Navigate • h/l: Fold • t: Mark • c: Clear • Enter: Play • Space: Pause • ←→: Seek • +/-: Volume • n/p: Next/Prev • r: Rescan • q: Quit";
 
     let status_bar = Paragraph::new(shortcuts)
         .style(Style::default().fg(Color::White))