🛡️ Sentinel: [CRITICAL] Fix XSS vulnerability in JSON-LD script tags

[hadsern]

🚨 Severity: CRITICAL
💡 Vulnerability: JSON.stringify does not automatically escape HTML control characters (<, >, &). The SchemaScript component takes this output and injects it into a <script> tag via dangerouslySetInnerHTML. If any schema strings contain </script><script>alert(1)</script>, the JSON stringification would maintain the < and > characters, allowing an attacker to break out of the JSON-LD script block and execute malicious JavaScript on the client.
🎯 Impact: This allows arbitrary JavaScript execution (XSS) on clients loading pages where schema is generated.
🔧 Fix: Manually string replace < and > with their JSON unicode escape equivalents (\\u003c and \\u003e).
✅ Verification: pnpm test, pnpm lint, and pnpm build have successfully run. The generated schema JSON output is correctly formatted and escaped.

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PR created automatically by Jules for task 13016380486855987287 started by @hadsern

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