Implement vim-style navigation and visual mode

- Add vim-style h key: closes folders and jumps to parent
- Implement stop() method in player for proper playback stopping
- Add space key to restart playback when stopped
- Add playlist color coding: green (playing), blue (paused), yellow (stopped)
- Fix n/p keys to preserve player state when switching tracks
- Implement vim-style visual mode with v key for multi-file selection
- Visual mode exits automatically on play/add actions
- Remove unused play_previous method
- Bump version to 0.1.7

src/player/mod.rs

@@ -187,6 +187,13 @@ impl Player {
         Ok(())
     }
 
+    pub fn stop(&mut self) -> Result<()> {
+        self.send_command("stop", &[])?;
+        self.is_idle = true;
+        self.position = 0.0;
+        self.duration = 0.0;
+        Ok(())
+    }
 
     pub fn set_volume(&mut self, volume: i64) -> Result<()> {
         self.send_command("set_property", &[json!("volume"), json!(volume)])?;