Add playlist support with marking and folder playback

- Mark files with 't' key (shown with * prefix in yellow)
- Clear marks with 'c' key
- Enter plays: marked files > whole folder > single file
- Navigate playlist with 'n' (next) and 'p' (previous)
- Show playlist position in status (e.g., "song.mp3 [3/10]")
- Collect all files recursively when playing folder
- Remove emoji icons from status panel
- Update help text with new keybindings

src/main.rs

@@ -113,14 +113,28 @@ async fn handle_key_event(state: &mut AppState, key_code: KeyCode) -> Result<()>
         KeyCode::Char('l') => {
             state.expand_selected();
         }
+        KeyCode::Char('t') => {
+            state.toggle_mark();
+        }
+        KeyCode::Char('c') => {
+            state.clear_marks();
+        }
+        KeyCode::Char('n') => {
+            state.play_next();
+            if let Some(ref path) = state.current_file {
+                tracing::info!("Next track: {:?}", path);
+            }
+        }
+        KeyCode::Char('p') => {
+            state.play_previous();
+            if let Some(ref path) = state.current_file {
+                tracing::info!("Previous track: {:?}", path);
+            }
+        }
         KeyCode::Enter => {
-            if let Some(item) = state.get_selected_item() {
-                if !item.node.is_dir {
-                    let path = item.node.path.clone();
-                    state.current_file = Some(path.clone());
-                    state.player_state = PlayerState::Playing;
-                    tracing::info!("Playing: {:?}", path);
-                }
+            state.play_selection();
+            if let Some(ref path) = state.current_file {
+                tracing::info!("Playing: {:?} (playlist: {} tracks)", path, state.playlist.len());
             }
         }
         KeyCode::Char(' ') => {

src/state/mod.rs

@@ -23,6 +23,9 @@ pub struct AppState {
     pub should_quit: bool,
     pub flattened_items: Vec<FlattenedItem>,
     pub expanded_dirs: HashSet<PathBuf>,
+    pub marked_files: HashSet<PathBuf>,
+    pub playlist: Vec<PathBuf>,
+    pub playlist_index: usize,
 }
 
 #[derive(Debug, Clone)]
@@ -52,6 +55,9 @@ impl AppState {
             should_quit: false,
             flattened_items,
             expanded_dirs,
+            marked_files: HashSet::new(),
+            playlist: Vec::new(),
+            playlist_index: 0,
         }
     }
 
@@ -105,6 +111,71 @@ impl AppState {
         }
     }
 
+    pub fn toggle_mark(&mut self) {
+        if let Some(item) = self.get_selected_item() {
+            if !item.node.is_dir {
+                let path = item.node.path.clone();
+                if self.marked_files.contains(&path) {
+                    self.marked_files.remove(&path);
+                } else {
+                    self.marked_files.insert(path);
+                }
+            }
+        }
+    }
+
+    pub fn clear_marks(&mut self) {
+        self.marked_files.clear();
+    }
+
+    pub fn play_selection(&mut self) {
+        // Priority: marked files > directory > single file
+        if !self.marked_files.is_empty() {
+            // Play marked files
+            self.playlist = self.marked_files.iter().cloned().collect();
+            self.playlist.sort();
+            self.playlist_index = 0;
+            if let Some(first) = self.playlist.first() {
+                self.current_file = Some(first.clone());
+                self.player_state = PlayerState::Playing;
+            }
+        } else if let Some(item) = self.get_selected_item() {
+            let node = item.node.clone();
+            if node.is_dir {
+                // Play all files in directory
+                self.playlist = collect_files_from_node(&node);
+                self.playlist_index = 0;
+                if let Some(first) = self.playlist.first() {
+                    self.current_file = Some(first.clone());
+                    self.player_state = PlayerState::Playing;
+                }
+            } else {
+                // Play single file
+                let path = node.path.clone();
+                self.playlist = vec![path.clone()];
+                self.playlist_index = 0;
+                self.current_file = Some(path);
+                self.player_state = PlayerState::Playing;
+            }
+        }
+    }
+
+    pub fn play_next(&mut self) {
+        if self.playlist_index + 1 < self.playlist.len() {
+            self.playlist_index += 1;
+            self.current_file = Some(self.playlist[self.playlist_index].clone());
+            self.player_state = PlayerState::Playing;
+        }
+    }
+
+    pub fn play_previous(&mut self) {
+        if self.playlist_index > 0 {
+            self.playlist_index -= 1;
+            self.current_file = Some(self.playlist[self.playlist_index].clone());
+            self.player_state = PlayerState::Playing;
+        }
+    }
+
     pub fn refresh_flattened_items(&mut self) {
         // Keep current expanded state after rescan
         self.rebuild_flattened_items();
@@ -137,3 +208,17 @@ fn flatten_tree(nodes: &[FileTreeNode], depth: usize, expanded_dirs: &HashSet<Pa
 
     result
 }
+
+fn collect_files_from_node(node: &FileTreeNode) -> Vec<PathBuf> {
+    let mut files = Vec::new();
+
+    if node.is_dir {
+        for child in &node.children {
+            files.extend(collect_files_from_node(child));
+        }
+    } else {
+        files.push(node.path.clone());
+    }
+
+    files
+}

src/ui/mod.rs

@@ -24,13 +24,16 @@ fn render_file_panel(frame: &mut Frame, state: &AppState, area: Rect) {
         .enumerate()
         .map(|(idx, item)| {
             let indent = "  ".repeat(item.depth);
+            let mark = if state.marked_files.contains(&item.node.path) { "* " } else { "" };
             let suffix = if item.node.is_dir { "/" } else { "" };
-            let text = format!("{}{}{}", indent, item.node.name, suffix);
+            let text = format!("{}{}{}{}", indent, mark, item.node.name, suffix);
 
             let style = if idx == state.selected_index {
                 Style::default().fg(Color::Black).bg(Color::Cyan)
             } else if item.node.is_dir {
                 Style::default().fg(Color::Blue)
+            } else if state.marked_files.contains(&item.node.path) {
+                Style::default().fg(Color::Yellow)
             } else {
                 Style::default()
             };
@@ -64,23 +67,30 @@ fn render_status_panel(frame: &mut Frame, state: &AppState, area: Rect) {
 
     // Player state
     let state_text = match state.player_state {
-        PlayerState::Stopped => "⏹ Stopped",
-        PlayerState::Playing => "▶ Playing",
-        PlayerState::Paused => "⏸ Paused",
+        PlayerState::Stopped => "Stopped",
+        PlayerState::Playing => "Playing",
+        PlayerState::Paused => "Paused",
     };
     let state_widget = Paragraph::new(state_text)
         .block(Block::default().borders(Borders::ALL).title("Status"))
         .style(Style::default().fg(Color::White));
     frame.render_widget(state_widget, chunks[0]);
 
-    // Current file
+    // Current file with playlist position
     let current_file = state
         .current_file
         .as_ref()
         .and_then(|p| p.file_name())
         .map(|n| n.to_string_lossy().to_string())
         .unwrap_or_else(|| "None".to_string());
-    let file_widget = Paragraph::new(current_file)
+
+    let playlist_info = if !state.playlist.is_empty() {
+        format!("{} [{}/{}]", current_file, state.playlist_index + 1, state.playlist.len())
+    } else {
+        current_file
+    };
+
+    let file_widget = Paragraph::new(playlist_info)
         .block(Block::default().borders(Borders::ALL).title("Current File"))
         .style(Style::default().fg(Color::White));
     frame.render_widget(file_widget, chunks[1]);
@@ -115,19 +125,31 @@ fn render_status_panel(frame: &mut Frame, state: &AppState, area: Rect) {
         Line::from(""),
         Line::from(vec![
             Span::styled("j/k", Style::default().fg(Color::Cyan)),
-            Span::raw(" Navigate down/up"),
+            Span::raw(" Navigate"),
         ]),
         Line::from(vec![
             Span::styled("h/l", Style::default().fg(Color::Cyan)),
-            Span::raw(" Collapse/expand dir"),
+            Span::raw(" Collapse/expand"),
+        ]),
+        Line::from(vec![
+            Span::styled("t", Style::default().fg(Color::Cyan)),
+            Span::raw(" Mark file"),
+        ]),
+        Line::from(vec![
+            Span::styled("c", Style::default().fg(Color::Cyan)),
+            Span::raw(" Clear marks"),
         ]),
         Line::from(vec![
             Span::styled("Enter", Style::default().fg(Color::Cyan)),
-            Span::raw(" Play file"),
+            Span::raw(" Play"),
         ]),
         Line::from(vec![
             Span::styled("Space", Style::default().fg(Color::Cyan)),
-            Span::raw(" Pause/Resume"),
+            Span::raw(" Pause"),
+        ]),
+        Line::from(vec![
+            Span::styled("n/p", Style::default().fg(Color::Cyan)),
+            Span::raw(" Next/Prev"),
         ]),
         Line::from(vec![
             Span::styled("r", Style::default().fg(Color::Cyan)),