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/setup/wizard_test.go

@@ -116,6 +116,148 @@ func TestSave_CreatesConfigDir(t *testing.T) {
 	}
 }
 
+func TestSave_DefaultPort(t *testing.T) {
+	dir := t.TempDir()
+	orig := os.Getenv("XDG_CONFIG_HOME")
+	os.Setenv("XDG_CONFIG_HOME", dir)
+	defer os.Setenv("XDG_CONFIG_HOME", orig)
+
+	cfg := config.Config{
+		NetBox: config.NetBoxConfig{URL: "http://x", Token: "t", TokenVersion: 1},
+		Cache:  config.CacheConfig{TTL: 60},
+		SSH:    config.SSHConfig{DefaultPort: 2222},
+	}
+	if err := save(cfg); err != nil {
+		t.Fatalf("save: %v", err)
+	}
+
+	data, _ := os.ReadFile(filepath.Join(dir, "netssh.yaml"))
+	if !strings.Contains(string(data), "default_port: 2222") {
+		t.Errorf("expected default_port: 2222 in config, got:\n%s", string(data))
+	}
+}
+
+func TestSave_Shortcuts_WritesSection(t *testing.T) {
+	dir := t.TempDir()
+	orig := os.Getenv("XDG_CONFIG_HOME")
+	os.Setenv("XDG_CONFIG_HOME", dir)
+	defer os.Setenv("XDG_CONFIG_HOME", orig)
+
+	cfg := config.Config{
+		NetBox: config.NetBoxConfig{URL: "http://x", Token: "t", TokenVersion: 1},
+		Cache:  config.CacheConfig{TTL: 60},
+		Shortcuts: config.ShortcutsConfig{
+			Domains:      []string{".example.com"},
+			StripHyphens: true,
+		},
+	}
+	if err := save(cfg); err != nil {
+		t.Fatalf("save: %v", err)
+	}
+
+	data, _ := os.ReadFile(filepath.Join(dir, "netssh.yaml"))
+	content := string(data)
+	for _, want := range []string{"shortcuts:", "domains:", ".example.com", "strip_hyphens: true"} {
+		if !strings.Contains(content, want) {
+			t.Errorf("expected %q in config, got:\n%s", want, content)
+		}
+	}
+}
+
+func TestSave_OmitsDefaultPortWhenZero(t *testing.T) {
+	dir := t.TempDir()
+	orig := os.Getenv("XDG_CONFIG_HOME")
+	os.Setenv("XDG_CONFIG_HOME", dir)
+	defer os.Setenv("XDG_CONFIG_HOME", orig)
+
+	cfg := config.Config{
+		NetBox: config.NetBoxConfig{URL: "http://x", Token: "t", TokenVersion: 1},
+		Cache:  config.CacheConfig{TTL: 60},
+		SSH:    config.SSHConfig{DefaultPort: 0},
+	}
+	if err := save(cfg); err != nil {
+		t.Fatalf("save: %v", err)
+	}
+
+	data, _ := os.ReadFile(filepath.Join(dir, "netssh.yaml"))
+	if strings.Contains(string(data), "default_port") {
+		t.Errorf("default_port should be omitted when zero, got:\n%s", string(data))
+	}
+}
+
+func TestSave_OmitsShortcutsWhenEmpty(t *testing.T) {
+	dir := t.TempDir()
+	orig := os.Getenv("XDG_CONFIG_HOME")
+	os.Setenv("XDG_CONFIG_HOME", dir)
+	defer os.Setenv("XDG_CONFIG_HOME", orig)
+
+	cfg := config.Config{
+		NetBox:    config.NetBoxConfig{URL: "http://x", Token: "t", TokenVersion: 1},
+		Cache:     config.CacheConfig{TTL: 60},
+		Shortcuts: config.ShortcutsConfig{}, // empty
+	}
+	if err := save(cfg); err != nil {
+		t.Fatalf("save: %v", err)
+	}
+
+	data, _ := os.ReadFile(filepath.Join(dir, "netssh.yaml"))
+	if strings.Contains(string(data), "shortcuts:") {
+		t.Errorf("shortcuts section should be omitted when empty, got:\n%s", string(data))
+	}
+}
+
+func TestSave_Roundtrip_WithNewFields(t *testing.T) {
+	dir := t.TempDir()
+	orig := os.Getenv("XDG_CONFIG_HOME")
+	os.Setenv("XDG_CONFIG_HOME", dir)
+	defer os.Setenv("XDG_CONFIG_HOME", orig)
+
+	original := config.Config{
+		NetBox: config.NetBoxConfig{
+			URL:          "https://netbox.example.com",
+			Token:        "nbt_test",
+			TokenVersion: 2,
+		},
+		SSH: config.SSHConfig{
+			DefaultUser: "admin",
+			DefaultPort: 2222,
+		},
+		Resolver: config.ResolverConfig{
+			Strategies: []string{"primary_ip"},
+		},
+		Cache: config.CacheConfig{TTL: 3600},
+		Shortcuts: config.ShortcutsConfig{
+			Domains:      []string{".example.com", ".example.de"},
+			StripHyphens: true,
+		},
+	}
+
+	if err := save(original); err != nil {
+		t.Fatalf("save: %v", err)
+	}
+
+	loaded, err := config.Load()
+	if err != nil {
+		t.Fatalf("Load after save: %v", err)
+	}
+
+	if loaded.SSH.DefaultPort != original.SSH.DefaultPort {
+		t.Errorf("DefaultPort: got %d, want %d", loaded.SSH.DefaultPort, original.SSH.DefaultPort)
+	}
+	if len(loaded.Shortcuts.Domains) != len(original.Shortcuts.Domains) {
+		t.Errorf("Shortcuts.Domains length: got %d, want %d", len(loaded.Shortcuts.Domains), len(original.Shortcuts.Domains))
+	} else {
+		for i, d := range original.Shortcuts.Domains {
+			if loaded.Shortcuts.Domains[i] != d {
+				t.Errorf("Shortcuts.Domains[%d]: got %q, want %q", i, loaded.Shortcuts.Domains[i], d)
+			}
+		}
+	}
+	if loaded.Shortcuts.StripHyphens != original.Shortcuts.StripHyphens {
+		t.Errorf("StripHyphens: got %v, want %v", loaded.Shortcuts.StripHyphens, original.Shortcuts.StripHyphens)
+	}
+}
+
 func TestParseStrategies(t *testing.T) {
 	tests := []struct {
 		in   string