Fix one focused bug + regression test (Python/TypeScript/JavaScript)

- Scope is one focused defect in a public Python, TypeScript, or JavaScript repository. - Deliverable identifies the root cause with exact file and symbol references. - Deliverable includes a minimal unified diff or complete replacement snippets for every changed file. - At least one regression test fails before the fix and passes after it, or the report clearly documents why automated reproduction is impossible. - Exact install, test, lint, and build commands are listed with observed results. - Existing public APIs and unrelated behavior remain unchanged unless the buyer explicitly requests otherwise. - No production credentials, private data, unauthorized security testing, deployment, or broad refactor is required. - Final output is self-contained, review-ready, and contains no guessed test results.