🛡️ Sentinel: [CRITICAL] Fix prototype pollution in label parsing

[ericbfriday]

🚨 Severity: CRITICAL
💡 Vulnerability: Prototype pollution in Lua labels parsing via __proto__ causing unexpected interactions with Object.prototype.
🎯 Impact: This could be exploited by user-supplied input where a label like ::__proto__:: could pollute the internal parser representation or cause parsing failures.
🔧 Fix: Replaced standard object initialization {} with Object.create(null) for the labels dictionary in luaparse.js.
✅ Verification: Tested parser manually with ::__proto__:: and ran all existing suite tests with npm run test which completed without regressions.

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PR created automatically by Jules for task 3511306698593960999 started by @ericbfriday

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[Copilot]

Pull request overview

This PR mitigates a prototype pollution risk in the Lua label (::label::) tracking logic by ensuring label names are stored in a dictionary that does not inherit from Object.prototype.

Changes:

• Initialize scope.labels with Object.create(null) to prevent special keys like __proto__ from affecting the object prototype chain.
• Add a Sentinel note documenting the vulnerability, lesson learned, and prevention guidance.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
luaparse.js	Uses a null-prototype dictionary for label storage to prevent prototype pollution via user-controlled label names.
.jules/sentinel.md	Documents the identified prototype pollution vector and the chosen mitigation pattern.

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