feat: initial commit of Git Automation CLI

- Add comprehensive Git workflow automation tools
- Include branch management utilities
- Add commit helpers with conventional commit support
- Implement GitHub integration for PR management
- Add configuration management system
- Include comprehensive test coverage
- Add professional documentation and examples

internal/config/config.go

@@ -0,0 +1,149 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"github.com/spf13/viper"
+)
+
+// Config represents the application configuration
+type Config struct {
+	// Git settings
+	DefaultRemote string `mapstructure:"default_remote"`
+	DefaultBranch string `mapstructure:"default_branch"`
+	
+	// GitHub settings
+	GitHubToken string `mapstructure:"github_token"`
+	GitHubURL   string `mapstructure:"github_url"`
+	
+	// Behavior settings
+	AutoCleanup    bool `mapstructure:"auto_cleanup"`
+	ConfirmDestructive bool `mapstructure:"confirm_destructive"`
+	DryRun         bool `mapstructure:"dry_run"`
+	Verbose        bool `mapstructure:"verbose"`
+	
+	// Branch settings
+	BranchPrefix   string `mapstructure:"branch_prefix"`
+	FeaturePrefix  string `mapstructure:"feature_prefix"`
+	HotfixPrefix   string `mapstructure:"hotfix_prefix"`
+}
+
+var (
+	// GlobalConfig holds the application configuration
+	GlobalConfig *Config
+	// configFile is the path to the configuration file
+	configFile string
+	// v is the viper instance
+	v *viper.Viper
+)
+
+// initViper initializes the viper instance
+func initViper() {
+	if v == nil {
+		v = viper.New()
+	}
+}
+
+// Init initializes the configuration
+func Init() error {
+	initViper()
+	
+	// Set default values
+	v.SetDefault("default_remote", "origin")
+	v.SetDefault("default_branch", "main")
+	v.SetDefault("github_url", "https://api.github.com")
+	v.SetDefault("auto_cleanup", false)
+	v.SetDefault("confirm_destructive", true)
+	v.SetDefault("dry_run", false)
+	v.SetDefault("verbose", false)
+	v.SetDefault("branch_prefix", "")
+	v.SetDefault("feature_prefix", "feature/")
+	v.SetDefault("hotfix_prefix", "hotfix/")
+
+	// Set configuration file paths
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return fmt.Errorf("could not get user home directory: %w", err)
+	}
+
+	configDir := filepath.Join(home, ".gitauto")
+	configFile = filepath.Join(configDir, "config.yaml")
+
+	// Ensure config directory exists
+	if err := os.MkdirAll(configDir, 0755); err != nil {
+		return fmt.Errorf("could not create config directory: %w", err)
+	}
+
+	// Set configuration file
+	v.SetConfigName("config")
+	v.SetConfigType("yaml")
+	v.AddConfigPath(configDir)
+	v.AddConfigPath(".")
+	
+	// Read environment variables
+	v.SetEnvPrefix("GITAUTO")
+	v.AutomaticEnv()
+
+	// Read configuration file
+	if err := v.ReadInConfig(); err != nil {
+		// It's okay if config file doesn't exist
+		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
+			return fmt.Errorf("could not read config file: %w", err)
+		}
+	}
+
+	// Unmarshal configuration
+	GlobalConfig = &Config{}
+	if err := v.Unmarshal(GlobalConfig); err != nil {
+		return fmt.Errorf("could not unmarshal config: %w", err)
+	}
+
+	return nil
+}
+
+// Save saves the current configuration to file
+func Save() error {
+	initViper()
+	
+	if err := v.WriteConfigAs(configFile); err != nil {
+		return fmt.Errorf("could not save config file: %w", err)
+	}
+	return nil
+}
+
+// GetConfigFile returns the path to the configuration file
+func GetConfigFile() string {
+	return configFile
+}
+
+// SetConfigFile sets the path to the configuration file (for testing)
+func SetConfigFile(path string) {
+	configFile = path
+}
+
+// Set sets a configuration value
+func Set(key string, value interface{}) {
+	initViper()
+	
+	v.Set(key, value)
+	// Update the global config
+	v.Unmarshal(GlobalConfig)
+}
+
+// Get gets a configuration value
+func Get(key string) interface{} {
+	initViper()
+	
+	return v.Get(key)
+}
+
+// SetViper sets the viper instance (for testing)
+func SetViper(viperInstance *viper.Viper) {
+	v = viperInstance
+}
+
+// ResetViper resets the viper instance (for testing)
+func ResetViper() {
+	v = nil
+}