feat: introduce theme management and performance improvements (#7)

cmd/themes.go

@@ -0,0 +1,24 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/karol-broda/snitch/internal/theme"
+	"github.com/spf13/cobra"
+)
+
+var themesCmd = &cobra.Command{
+	Use:   "themes",
+	Short: "List available themes",
+	Run: func(cmd *cobra.Command, args []string) {
+		fmt.Printf("Available themes (default: %s):\n\n", theme.DefaultTheme)
+		for _, name := range theme.ListThemes() {
+			fmt.Printf("  %s\n", name)
+		}
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(themesCmd)
+}
+