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/config/keybindings_test.go

@@ -0,0 +1,181 @@
+package config
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestDefaultKeyBindings(t *testing.T) {
+	kb := GetDefaultKeyBindings()
+
+	// Test default configuration
+	if kb.DisableEscQuit {
+		t.Error("Default configuration should allow ESC to quit (backward compatibility)")
+	}
+
+	// Test default quit keys
+	expectedQuitKeys := []string{"q", "ctrl+c"}
+	if len(kb.QuitKeys) != len(expectedQuitKeys) {
+		t.Errorf("Expected %d quit keys, got %d", len(expectedQuitKeys), len(kb.QuitKeys))
+	}
+
+	for i, expected := range expectedQuitKeys {
+		if i >= len(kb.QuitKeys) || kb.QuitKeys[i] != expected {
+			t.Errorf("Expected quit key %s, got %s", expected, kb.QuitKeys[i])
+		}
+	}
+}
+
+func TestShouldQuitOnKey(t *testing.T) {
+	tests := []struct {
+		name           string
+		keyBindings    KeyBindings
+		key            string
+		expectedResult bool
+	}{
+		{
+			name: "Default config - ESC should quit",
+			keyBindings: KeyBindings{
+				QuitKeys:       []string{"q", "ctrl+c"},
+				DisableEscQuit: false,
+			},
+			key:            "esc",
+			expectedResult: true,
+		},
+		{
+			name: "Disabled ESC quit - ESC should not quit",
+			keyBindings: KeyBindings{
+				QuitKeys:       []string{"q", "ctrl+c"},
+				DisableEscQuit: true,
+			},
+			key:            "esc",
+			expectedResult: false,
+		},
+		{
+			name: "Q key should quit",
+			keyBindings: KeyBindings{
+				QuitKeys:       []string{"q", "ctrl+c"},
+				DisableEscQuit: true,
+			},
+			key:            "q",
+			expectedResult: true,
+		},
+		{
+			name: "Ctrl+C should quit",
+			keyBindings: KeyBindings{
+				QuitKeys:       []string{"q", "ctrl+c"},
+				DisableEscQuit: true,
+			},
+			key:            "ctrl+c",
+			expectedResult: true,
+		},
+		{
+			name: "Other keys should not quit",
+			keyBindings: KeyBindings{
+				QuitKeys:       []string{"q", "ctrl+c"},
+				DisableEscQuit: true,
+			},
+			key:            "enter",
+			expectedResult: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := tt.keyBindings.ShouldQuitOnKey(tt.key)
+			if result != tt.expectedResult {
+				t.Errorf("ShouldQuitOnKey(%q) = %v, expected %v", tt.key, result, tt.expectedResult)
+			}
+		})
+	}
+}
+
+func TestAppConfigBasics(t *testing.T) {
+	// Test default config creation
+	defaultConfig := GetDefaultAppConfig()
+
+	if defaultConfig.KeyBindings.DisableEscQuit {
+		t.Error("Default configuration should allow ESC to quit")
+	}
+
+	expectedQuitKeys := []string{"q", "ctrl+c"}
+	if len(defaultConfig.KeyBindings.QuitKeys) != len(expectedQuitKeys) {
+		t.Errorf("Expected %d quit keys, got %d", len(expectedQuitKeys), len(defaultConfig.KeyBindings.QuitKeys))
+	}
+}
+
+func TestMergeWithDefaults(t *testing.T) {
+	// Test config with missing QuitKeys
+	incompleteConfig := AppConfig{
+		KeyBindings: KeyBindings{
+			DisableEscQuit: true,
+			// QuitKeys is missing
+		},
+	}
+
+	mergedConfig := mergeWithDefaults(incompleteConfig)
+
+	// Should preserve DisableEscQuit
+	if !mergedConfig.KeyBindings.DisableEscQuit {
+		t.Error("Should preserve DisableEscQuit as true")
+	}
+
+	// Should fill in default QuitKeys
+	expectedQuitKeys := []string{"q", "ctrl+c"}
+	if len(mergedConfig.KeyBindings.QuitKeys) != len(expectedQuitKeys) {
+		t.Errorf("Expected %d quit keys, got %d", len(expectedQuitKeys), len(mergedConfig.KeyBindings.QuitKeys))
+	}
+}
+
+func TestSaveAndLoadAppConfigIntegration(t *testing.T) {
+	// Create a temporary directory for testing
+	tempDir, err := os.MkdirTemp("", "sshm_test")
+	if err != nil {
+		t.Fatalf("Failed to create temp directory: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	// Create a custom config file directly in temp directory
+	configPath := filepath.Join(tempDir, "config.json")
+
+	customConfig := AppConfig{
+		KeyBindings: KeyBindings{
+			QuitKeys:       []string{"q"},
+			DisableEscQuit: true,
+		},
+	}
+
+	// Save config directly to file
+	data, err := json.MarshalIndent(customConfig, "", "  ")
+	if err != nil {
+		t.Fatalf("Failed to marshal config: %v", err)
+	}
+
+	err = os.WriteFile(configPath, data, 0644)
+	if err != nil {
+		t.Fatalf("Failed to write config file: %v", err)
+	}
+
+	// Read and unmarshal config
+	readData, err := os.ReadFile(configPath)
+	if err != nil {
+		t.Fatalf("Failed to read config file: %v", err)
+	}
+
+	var loadedConfig AppConfig
+	err = json.Unmarshal(readData, &loadedConfig)
+	if err != nil {
+		t.Fatalf("Failed to unmarshal config: %v", err)
+	}
+
+	// Verify the loaded config matches what we saved
+	if !loadedConfig.KeyBindings.DisableEscQuit {
+		t.Error("DisableEscQuit should be true")
+	}
+
+	if len(loadedConfig.KeyBindings.QuitKeys) != 1 || loadedConfig.KeyBindings.QuitKeys[0] != "q" {
+		t.Errorf("Expected quit keys to be ['q'], got %v", loadedConfig.KeyBindings.QuitKeys)
+	}
+}