🛡️ Sentinel: [MEDIUM] Fix sensitive object key redaction bypass

[google-labs-jules]

• 🚨 Severity: MEDIUM
• 💡 Vulnerability: The sanitizeObject utility redacted entire headers objects but failed to redact specific sensitive keys (like authorization, password, or token) if they were logged independently or at the top level of an object structure. Furthermore, the check was case-sensitive.
• 🎯 Impact: Sensitive user credentials or API tokens could inadvertently leak into application logs or telemetry if passed directly into an object structure rather than nested under headers.
• 🔧 Fix: Added explicit redaction for common sensitive keys (authorization, cookie, token, password, secret, credential) in sanitizeObject and made the check case-insensitive.
• ✅ Verification: Ran bun run test:full and verified that object sanitization logic correctly hides these values.

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PR created automatically by Jules for task 9156442890077417948 started by @YoungSx

[google-labs-jules]

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