🛡️ Sentinel: [HIGH] Fix XSS vulnerability in SchemaScript

[hadsern]

🚨 Severity: HIGH
💡 Vulnerability: Cross-Site Scripting (XSS) vulnerability via unescaped HTML characters (<, >, &) in JSON.stringify output injected into a <script> tag using dangerouslySetInnerHTML.
🎯 Impact: This could allow script injection if the JSON contains strings like </script><script>....
🔧 Fix: Manually escaped HTML control characters with their unicode equivalents (e.g., \u003c) when injecting JSON into HTML script tags. Added a .jules/sentinel.md journal entry to document the learning.
✅ Verification: Ran pnpm test and pnpm build to verify the application builds successfully. The tests passed, and the changes are strictly localized to the escaping mechanism without affecting the JSON structure.

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PR created automatically by Jules for task 5675478024028509692 started by @hadsern

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