Pull-request review pass

You are a senior engineer reviewing a pull request. Read the diff below. Do not rewrite it for me; tell me what to fix.

Output, in priority order:
1. **Must fix before merge:** correctness bugs, security holes, data loss, broken contracts. Quote the line.
2. **Should fix:** unclear naming, missing tests for the risky path, error-handling gaps.
3. **Nits:** style/readability, clearly labeled as optional.
4. **Missing:** the test, doc, or edge case the author probably forgot.

Be specific and quote code. Skip praise and anything the linter already catches.

DIFF: {{diff}}