feat: add --no-update-check flag and disable update check via config (issue #23)

Add support for disabling the automatic update check at startup, which could cause delays on air-gapped or offline machines due to DNS timeouts.

- Add --no-update-check CLI flag for one-time override
- Add check_for_updates field (*bool) to AppConfig with default true
- CLI flag overrides the config file setting (both feed into IsUpdateCheckEnabled)
- Move update check from --version template to TUI Init() only, respecting the new configuration
- Remove getVersionWithUpdateCheck() from cmd/root.go; --version now prints a plain version string
- Rename internal/config/keybindings.go → appconfig.go and keybindings_test.go → appconfig_test.go to reflect the broader scope of the file
- Add TestIsUpdateCheckEnabled with table-driven cases (nil config, nil field, true, false) and extend existing integration test with a CheckForUpdates round-trip
- Update README: document --no-update-check flag, config option, and rename "Custom Key Bindings" section to "Application Configuration"

internal/config/appconfig.go

@@ -18,7 +18,16 @@ type KeyBindings struct {
 
 // AppConfig represents the main application configuration
 type AppConfig struct {
-	KeyBindings KeyBindings `json:"key_bindings"`
+	CheckForUpdates *bool       `json:"check_for_updates,omitempty"`
+	KeyBindings     KeyBindings `json:"key_bindings"`
+}
+
+// IsUpdateCheckEnabled returns true if the update check is enabled (default: true)
+func (c *AppConfig) IsUpdateCheckEnabled() bool {
+	if c == nil || c.CheckForUpdates == nil {
+		return true
+	}
+	return *c.CheckForUpdates
 }
 
 // GetDefaultKeyBindings returns the default key bindings configuration

internal/config/appconfig_test.go

@@ -104,6 +104,58 @@ func TestAppConfigBasics(t *testing.T) {
 	if len(defaultConfig.KeyBindings.QuitKeys) != len(expectedQuitKeys) {
 		t.Errorf("Expected %d quit keys, got %d", len(expectedQuitKeys), len(defaultConfig.KeyBindings.QuitKeys))
 	}
+
+	// CheckForUpdates should be nil by default
+	if defaultConfig.CheckForUpdates != nil {
+		t.Error("Default configuration should have CheckForUpdates as nil")
+	}
+
+	// IsUpdateCheckEnabled should return true by default
+	if !defaultConfig.IsUpdateCheckEnabled() {
+		t.Error("IsUpdateCheckEnabled should return true when CheckForUpdates is nil")
+	}
+}
+
+func boolPtr(b bool) *bool {
+	return &b
+}
+
+func TestIsUpdateCheckEnabled(t *testing.T) {
+	tests := []struct {
+		name     string
+		config   *AppConfig
+		expected bool
+	}{
+		{
+			name:     "nil AppConfig returns true",
+			config:   nil,
+			expected: true,
+		},
+		{
+			name:     "CheckForUpdates nil returns true",
+			config:   &AppConfig{},
+			expected: true,
+		},
+		{
+			name:     "CheckForUpdates true returns true",
+			config:   &AppConfig{CheckForUpdates: boolPtr(true)},
+			expected: true,
+		},
+		{
+			name:     "CheckForUpdates false returns false",
+			config:   &AppConfig{CheckForUpdates: boolPtr(false)},
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := tt.config.IsUpdateCheckEnabled()
+			if result != tt.expected {
+				t.Errorf("IsUpdateCheckEnabled() = %v, expected %v", result, tt.expected)
+			}
+		})
+	}
 }
 
 func TestMergeWithDefaults(t *testing.T) {
@@ -141,6 +193,7 @@ func TestSaveAndLoadAppConfigIntegration(t *testing.T) {
 	configPath := filepath.Join(tempDir, "config.json")
 
 	customConfig := AppConfig{
+		CheckForUpdates: boolPtr(false),
 		KeyBindings: KeyBindings{
 			QuitKeys:       []string{"q"},
 			DisableEscQuit: true,
@@ -178,4 +231,15 @@ func TestSaveAndLoadAppConfigIntegration(t *testing.T) {
 	if len(loadedConfig.KeyBindings.QuitKeys) != 1 || loadedConfig.KeyBindings.QuitKeys[0] != "q" {
 		t.Errorf("Expected quit keys to be ['q'], got %v", loadedConfig.KeyBindings.QuitKeys)
 	}
+
+	// Verify CheckForUpdates is correctly persisted and reloaded
+	if loadedConfig.CheckForUpdates == nil {
+		t.Fatal("CheckForUpdates should not be nil after round-trip")
+	}
+	if *loadedConfig.CheckForUpdates != false {
+		t.Errorf("CheckForUpdates should be false after round-trip, got %v", *loadedConfig.CheckForUpdates)
+	}
+	if loadedConfig.IsUpdateCheckEnabled() {
+		t.Error("IsUpdateCheckEnabled should return false when CheckForUpdates is false")
+	}
 }

internal/ui/tui.go

@@ -16,7 +16,7 @@ import (
 )
 
 // NewModel creates a new TUI model with the given SSH hosts
-func NewModel(hosts []config.SSHHost, configFile string, searchMode bool, currentVersion string) Model {
+func NewModel(hosts []config.SSHHost, configFile string, searchMode bool, currentVersion string, noUpdateCheck bool) Model {
 	// Load application configuration
 	appConfig, err := config.LoadAppConfig()
 	if err != nil {
@@ -26,6 +26,12 @@ func NewModel(hosts []config.SSHHost, configFile string, searchMode bool, curren
 		appConfig = &defaultConfig
 	}
 
+	// CLI flag overrides config file setting
+	if noUpdateCheck {
+		f := false
+		appConfig.CheckForUpdates = &f
+	}
+
 	// Initialize the history manager
 	historyManager, err := history.NewHistoryManager()
 	if err != nil {
@@ -151,8 +157,8 @@ func NewModel(hosts []config.SSHHost, configFile string, searchMode bool, curren
 }
 
 // RunInteractiveMode starts the interactive TUI interface
-func RunInteractiveMode(hosts []config.SSHHost, configFile string, searchMode bool, currentVersion string) error {
-	m := NewModel(hosts, configFile, searchMode, currentVersion)
+func RunInteractiveMode(hosts []config.SSHHost, configFile string, searchMode bool, currentVersion string, noUpdateCheck bool) error {
+	m := NewModel(hosts, configFile, searchMode, currentVersion, noUpdateCheck)
 
 	// Start the application in alt screen mode for clean output
 	p := tea.NewProgram(m, tea.WithAltScreen())

internal/ui/update.go

@@ -74,8 +74,8 @@ func (m Model) Init() tea.Cmd {
 	// Basic initialization commands
 	cmds = append(cmds, textinput.Blink)
 
-	// Check for version updates if we have a current version
-	if m.currentVersion != "" {
+	// Check for version updates if we have a current version and updates are enabled
+	if m.currentVersion != "" && m.appConfig.IsUpdateCheckEnabled() {
 		cmds = append(cmds, checkVersionCmd(m.currentVersion))
 	}