🧹 Refactor buildEntry to extract logic into helpers

[akutuva21]

🎯 What: The buildEntry function in scripts/generate-manifest.js was refactored. The non-slim fields logic and collection logic were extracted out of the main function and into separate helper functions (addSlimFields and addCollectionFields).

💡 Why: This refactoring simplifies the buildEntry function, making it shorter, easier to read, and simpler to maintain, as each discrete step of the manifest generation is now contained in its own well-defined utility function.

✅ Verification: The refactored code successfully passed the complete test suite. Specifically, node --test scripts/generate-manifest.test.js passed, demonstrating that the output behavior of the script remained identical.

✨ Result: A much cleaner buildEntry function that delegates complex parts of entry building to focused utility functions.

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PR created automatically by Jules for task 15992505536613470810 started by @akutuva21

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