test: avoid install-skill race pattern

Author: kjgbot

src/cli/lib/install-skill.test.ts

@@ -37,11 +37,16 @@ describe('installSkill', () => {
       expect(dirStat.isDirectory()).toBe(true);
       expect(dirStat.mode & 0o777).toBe(0o755);
 
-      const fileStat = await fs.stat(result.destPath);
-      expect(fileStat.mode & 0o777).toBe(0o644);
-
-      const written = await fs.readFile(result.destPath, 'utf-8');
-      expect(written).toBe(SOURCE_BODY_V1);
+      const handle = await fs.open(result.destPath, 'r');
+      try {
+        const fileStat = await handle.stat();
+        expect(fileStat.mode & 0o777).toBe(0o644);
+
+        const written = await handle.readFile('utf-8');
+        expect(written).toBe(SOURCE_BODY_V1);
+      } finally {
+        await handle.close();
+      }
     } finally {
       process.umask(originalUmask);
     }