add: accent color option in config

src/app.rs

@@ -165,6 +165,7 @@ pub struct App {
     pub volume: u8,
     pub shuffle: bool,
     pub repeat: RepeatMode,
+    pub accent: ratatui::style::Color,
     played: HashSet<usize>,
     fail_streak: u8,
     result_cursor: Option<usize>,
@@ -241,6 +242,7 @@ impl App {
             volume: p.volume,
             shuffle: p.shuffle,
             repeat: p.repeat,
+            accent: cfg.ui.accent,
             played: HashSet::new(),
             fail_streak: 0,
             result_cursor: None,