feat: enhance settings modal input handling (#21)

- Change settings key from S back to comma (,) for consistency
- Add vim-style navigation: k/j for up/down movement
- Add Space as alternative to Enter for theme selection
- Remove T key theme toggle functionality (now modal-only)
- Update footer to show enhanced key bindings
- Maintain backward compatibility with arrow keys

Resolves #21

Author: gitcoder89431

src/events.rs

@@ -55,11 +55,10 @@ impl EventHandler {
                     match key_event.code {
                         KeyCode::Char('q') => Ok(AppEvent::Quit),
                         KeyCode::Esc => Ok(AppEvent::CloseSettings),
-                        KeyCode::Char('s') | KeyCode::Char('S') => Ok(AppEvent::OpenSettings),
-                        KeyCode::Char('t') | KeyCode::Char('T') => Ok(AppEvent::ToggleTheme),
-                        KeyCode::Up => Ok(AppEvent::NavigateUp),
-                        KeyCode::Down => Ok(AppEvent::NavigateDown),
-                        KeyCode::Enter => Ok(AppEvent::Select),
+                        KeyCode::Char(',') => Ok(AppEvent::OpenSettings),
+                        KeyCode::Up | KeyCode::Char('k') => Ok(AppEvent::NavigateUp),
+                        KeyCode::Down | KeyCode::Char('j') => Ok(AppEvent::NavigateDown),
+                        KeyCode::Enter | KeyCode::Char(' ') => Ok(AppEvent::Select),
                         KeyCode::Char('c')
                             if key_event.modifiers.contains(KeyModifiers::CONTROL) =>
                         {

src/ui/app.rs

@@ -186,9 +186,8 @@ impl App {
                 }
             }
             AppEvent::ToggleTheme => {
-                // Toggle theme through settings system
-                self.settings.get_mut().toggle_theme();
-                self.settings.get().apply_theme(&mut self.theme);
+                // T key functionality removed in Issue #21
+                // Theme changes now only available through settings modal
             }
             AppEvent::Resize(width, height) => {
                 self.last_size = Some((width, height));
@@ -371,11 +370,11 @@ impl App {
 
         let footer_text = match self.state {
             AppState::Main => format!(
-                "ESC/q: Quit | T: Toggle Theme | S: Settings | Current: [{}] | Production v0.1.0",
+                "ESC/q: Quit | ,: Settings | Current: [{}] | Production v0.1.0",
                 current_theme
             ),
             AppState::Settings => format!(
-                "ESC: Back to Main | T: Toggle Theme | Current: [{}] | Settings Mode",
+                "ESC: Back to Main | ↑↓/kj: Navigate | Enter/Space: Select | Current: [{}]",
                 current_theme
             ),
             AppState::Quitting => "Application shutting down gracefully...".to_string(),