🛡️ Sentinel: [CRITICAL] Fix command injection in id lookups

[Donach]

🚨 Severity: CRITICAL
💡 Vulnerability: Unsanitized user inputs (group names and usernames) were being string-interpolated directly into system commands executed using execSync. Since execSync evaluates commands within a shell (/bin/sh), attackers could inject arbitrary OS commands using shell metacharacters (e.g., ; rm -rf /).
🎯 Impact: Allowed unrestricted Arbitrary Command Execution on the host system as the Node.js process user.
🔧 Fix: Replaced execSync with execFileSync across id-lookups.ts. This bypasses shell execution altogether. Furthermore, we implemented the -- double-dash operator before dynamic inputs (['group', '--', groupName]) to securely delimit the executable flags, neutralizing "argument injection" if inputs start with hyphens.
✅ Verification: Unit tests for related functionality passing successfully. Lint and build verified.

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PR created automatically by Jules for task 3309621675663281814 started by @Donach

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