feat: introduce shortcuts and shell hook support

- **Shortcuts**: Add hostname normalization with domain stripping and hyphen folding. Include alias generation for cached hosts.
- **Shell Hook**: Automate 24h cache refresh trigger with shell startup hook. Add install/uninstall commands for bash, zsh, and fish.
- **Wizard**: Extend setup wizard to configure shortcuts (domains, hyphen stripping) and default SSH port.
- **Cache**: Add `GetByShortcut` for resolving hosts via normalized shortcuts. Implement `NeedsRefresh` / `SetRefreshed` logic for refresh timestamps.
- **Tests**: Comprehensive unit tests for shortcuts, hook installation, cache refresh, and alias generation.
- **Docs**: Update README with shortcuts, shell hook, and default SSH port configuration.

internal/config/config.go

@@ -10,10 +10,11 @@ import (
 )
 
 type Config struct {
-	NetBox   NetBoxConfig   `mapstructure:"netbox"`
-	Resolver ResolverConfig `mapstructure:"resolver"`
-	Cache    CacheConfig    `mapstructure:"cache"`
-	SSH      SSHConfig      `mapstructure:"ssh"`
+	NetBox    NetBoxConfig    `mapstructure:"netbox"`
+	Resolver  ResolverConfig  `mapstructure:"resolver"`
+	Cache     CacheConfig     `mapstructure:"cache"`
+	SSH       SSHConfig       `mapstructure:"ssh"`
+	Shortcuts ShortcutsConfig `mapstructure:"shortcuts"`
 }
 
 type NetBoxConfig struct {
@@ -35,6 +36,12 @@ type CacheConfig struct {
 
 type SSHConfig struct {
 	DefaultUser string `mapstructure:"default_user"`
+	DefaultPort int    `mapstructure:"default_port"`
+}
+
+type ShortcutsConfig struct {
+	Domains      []string `mapstructure:"domains"`
+	StripHyphens bool     `mapstructure:"strip_hyphens"`
 }
 
 // Path returns the canonical config file path.