fix: address latest PR review feedback

launcher/parse-args.test.ts

@@ -2,6 +2,34 @@ import test from 'node:test';
 import assert from 'node:assert/strict';
 import { parseArgs } from './config';
 
+class ExitSignal extends Error {
+  code: number;
+
+  constructor(code: number) {
+    super(`exit:${code}`);
+    this.code = code;
+  }
+}
+
+function withProcessExitIntercept(callback: () => void): ExitSignal {
+  const originalExit = process.exit;
+  try {
+    process.exit = ((code?: number) => {
+      throw new ExitSignal(code ?? 0);
+    }) as typeof process.exit;
+    callback();
+  } catch (error) {
+    if (error instanceof ExitSignal) {
+      return error;
+    }
+    throw error;
+  } finally {
+    process.exit = originalExit;
+  }
+
+  throw new Error('expected parseArgs to exit');
+}
+
 test('parseArgs captures passthrough args for app subcommand', () => {
   const parsed = parseArgs(['app', '--anilist', '--log-level', 'debug'], 'subminer', {});
 
@@ -119,6 +147,15 @@ test('parseArgs maps lifetime stats cleanup flag', () => {
   assert.equal(parsed.statsCleanupLifetime, true);
 });
 
+test('parseArgs rejects cleanup-only stats flags without cleanup action', () => {
+  const error = withProcessExitIntercept(() => {
+    parseArgs(['stats', '--vocab'], 'subminer', {});
+  });
+
+  assert.equal(error.code, 1);
+  assert.match(error.message, /exit:1/);
+});
+
 test('parseArgs maps stats rebuild action to cleanup lifetime mode', () => {
   const parsed = parseArgs(['stats', 'rebuild'], 'subminer', {});