test(ci): add env isolation comment to persist-command-handler

Align with claudecode-env-stripping.test.ts style — explain why
CLAUDE_CONFIG_DIR is cleared in beforeEach for consistency across
test files.

Built [OnSteroids](https://onsteroids.ai)

tests/unit/commands/persist-command-handler.test.ts

@@ -73,6 +73,7 @@ function stubProcessExit(): void {
 beforeEach(async () => {
   tempRoot = await fs.promises.mkdtemp(path.join(os.tmpdir(), 'ccs-persist-handler-test-'));
   originalClaudeConfigDir = process.env.CLAUDE_CONFIG_DIR;
+  // Clear CLAUDE_CONFIG_DIR so scoped CCS_HOME takes effect (leaks from host CCS session)
   delete process.env.CLAUDE_CONFIG_DIR;
   originalProcessExit = process.exit;
   originalFsOpen = fs.promises.open;