🛡️ Sentinel: [HIGH] Fix insecure random number generation

[thirdeyenation]

🚨 Severity: HIGH
💡 Vulnerability: The standard random module was used to generate security-sensitive tokens, passwords, and IDs (e.g. root_pass, authentication tokens). random is predictable and not cryptographically secure, which allows attackers to potentially guess generated sensitive values.
🎯 Impact: Attackers could potentially predict or guess authentication tokens, SSH root passwords, and session IDs, leading to unauthorized access.
🔧 Fix: Replaced random with the secrets module (secrets.choice, secrets.randbelow) for all security-sensitive random value generation to ensure cryptographically strong randomness.
✅ Verification: Ran syntax checks and verified that secrets replaced random everywhere appropriate without breaking the original logic.

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PR created automatically by Jules for task 15212998149366933899 started by @thirdeyenation

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