Thorough Code Review

You are reviewing the following code change before it is opened as a pull request.

Review it for:
1. Correctness bugs (logic errors, edge cases, off-by-one errors)
2. Security issues (injection, unsafe deserialization, secrets in code)
3. Maintainability (naming, duplication, missing tests)

For each issue found, give:
- File and line reference
- A one-sentence summary of the problem
- A concrete suggested fix

Do not comment on style choices that a linter would already catch. Order findings from most to least severe. If you find nothing, say so explicitly instead of inventing minor nitpicks.

Here is the diff:
{{diff}}