feat: completion + README — polish and docs

internal/cmd/root.go

@@ -88,4 +88,24 @@ func init() {
 	rootCmd.PersistentFlags().StringVarP(&flagOutput, "output", "o", "", "Output format: table, json, yaml, raw")
 	rootCmd.PersistentFlags().BoolVar(&flagRaw, "raw", false, "Output raw API response")
 	rootCmd.PersistentFlags().BoolVar(&flagDebug, "debug", false, "Enable debug output")
+
+	completionCmd := &cobra.Command{
+		Use:   "completion [bash|zsh|fish]",
+		Short: "Generate shell completion script",
+		Annotations: map[string]string{"skipProvider": "true"},
+		Args:  cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			switch args[0] {
+			case "bash":
+				return rootCmd.GenBashCompletion(os.Stdout)
+			case "zsh":
+				return rootCmd.GenZshCompletion(os.Stdout)
+			case "fish":
+				return rootCmd.GenFishCompletion(os.Stdout, true)
+			default:
+				return fmt.Errorf("unsupported shell: %s", args[0])
+			}
+		},
+	}
+	rootCmd.AddCommand(completionCmd)
 }