feat: add configurable key bindings with ESC quit disable option

- Add unified application configuration system with JSON config file
- Implement configurable quit keys (default: "q", "ctrl+c")
- Add disable_esc_quit option for vim users to prevent accidental exits
- Auto-create default config file at ~/.config/sshm/config.json
- Maintain backward compatibility (ESC quit enabled by default)
- Include comprehensive tests and documentation

internal/ui/model.go

@@ -80,6 +80,9 @@ type Model struct {
 	sortMode       SortMode
 	configFile     string // Path to the SSH config file
 
+	// Application configuration
+	appConfig      *config.AppConfig
+
 	// Version update information
 	updateInfo     *version.UpdateInfo
 	currentVersion string

internal/ui/tui.go

@@ -17,6 +17,15 @@ import (
 
 // NewModel creates a new TUI model with the given SSH hosts
 func NewModel(hosts []config.SSHHost, configFile, currentVersion string) Model {
+	// Load application configuration
+	appConfig, err := config.LoadAppConfig()
+	if err != nil {
+		// Log the error but continue with default configuration
+		fmt.Printf("Warning: Could not load application config: %v, using defaults\n", err)
+		defaultConfig := config.GetDefaultAppConfig()
+		appConfig = &defaultConfig
+	}
+
 	// Initialize the history manager
 	historyManager, err := history.NewHistoryManager()
 	if err != nil {
@@ -39,6 +48,7 @@ func NewModel(hosts []config.SSHHost, configFile, currentVersion string) Model {
 		sortMode:       SortByName,
 		configFile:     configFile,
 		currentVersion: currentVersion,
+		appConfig:      appConfig,
 		styles:         styles,
 		width:          80,
 		height:         24,

internal/ui/update.go

@@ -445,8 +445,9 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 func (m Model) handleListViewKeys(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	var cmd tea.Cmd
+	key := msg.String()
 
-	switch msg.String() {
+	switch key {
 	case "esc", "ctrl+c":
 		if m.deleteMode {
 			// Exit delete mode
@@ -455,10 +456,16 @@ func (m Model) handleListViewKeys(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 			m.table.Focus()
 			return m, nil
 		}
-		return m, tea.Quit
+		// Use configurable key bindings for quit
+		if m.appConfig != nil && m.appConfig.KeyBindings.ShouldQuitOnKey(key) {
+			return m, tea.Quit
+		}
 	case "q":
 		if !m.searchMode && !m.deleteMode {
-			return m, tea.Quit
+			// Use configurable key bindings for quit
+			if m.appConfig != nil && m.appConfig.KeyBindings.ShouldQuitOnKey(key) {
+				return m, tea.Quit
+			}
 		}
 	case "/", "ctrl+f":
 		if !m.searchMode && !m.deleteMode {