🧪 [testing] add tests for parseScalar in validate-metadata.js

[akutuva21]

🎯 What: The parseScalar utility function in scripts/validate-metadata.js lacked test coverage, despite being a pure function responsible for critical metadata parsing (e.g. types like booleans, arrays, numbers, and strings).

📊 Coverage: The new tests in scripts/tests/validate-metadata.test.js cover:

• Boolean strings ("true", "false")
• Null string ("null")
• Numeric strings ("42", "-10", "0")
• Array representations ("[]", "["a", "b"]")
• Double-quoted strings ('"hello"')
• Plain strings fallback ("hello", "")
• Handling surrounding whitespaces

✨ Result: A safer parsing layer with automated verification. The parseScalar logic is now directly verifiable, establishing a safety net for future refactoring and improvements to metadata validation.

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PR created automatically by Jules for task 16219869687540900783 started by @akutuva21

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[akutuva21]

Reviewed in sequence (tests first). parseScalar test coverage looks good, and branch now keeps exports additive to reduce cross-PR conflicts.