test: add unit tests for code_execution_utils.ts

[nuthalapativarun]

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Link to Issue or Description of Change

Add unit test coverage for code_execution_utils.ts — 283-line utility module with zero test coverage.

Testing Plan

Unit Tests:

• Added unit tests for all exported functions in code_execution_utils.ts
• All unit tests pass locally

Manual E2E Tests:

• N/A (pure unit tests)

Checklist

• Read CONTRIBUTING.md
• Self-reviewed code
• Commented hard-to-understand areas
• Added tests proving fix/feature works
• Unit tests pass locally
• Manually tested end-to-end
• Dependent changes merged/published