Review this pull request. Context: [what it should do, link to issue]. Language/framework: [stack].
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Report in this order: 1) Bugs and correctness issues, 2) Security issues, 3) Missing tests, 4) Maintainability. For each finding give severity (blocker/major/minor/nit), the file and line, why it matters, and a concrete fix (code if short). Don't comment on style that a linter would catch. End with a verdict: approve, approve with changes, or request changes.