feat: CLI 错误输出格式化

src/cli/output.ts

@@ -0,0 +1,20 @@
+import { CliError } from "./errors.ts";
+
+export function formatError(error: CliError): string {
+  const parts: string[] = [`错误: ${error.message}`];
+
+  if (error.usage) {
+    parts.push(`用法: ${error.usage}`);
+  }
+
+  if (error.hint) {
+    parts.push(`提示: ${error.hint}`);
+  }
+
+  return parts.join("\n\n");
+}
+
+export function printError(error: CliError): never {
+  process.stderr.write(formatError(error) + "\n");
+  process.exit(1);
+}