🛡️ Sentinel: [HIGH] Fix insecure random token generation

[thirdeyenation]

🚨 Severity: HIGH
💡 Vulnerability: Randomness for security-sensitive tokens (such as AdHocTask tokens and guids) was being generated using the insecure random module (via random.randint and random.choices). The random module uses a predictable PRNG, which could allow attackers to predict tokens.
🎯 Impact: Attackers could potentially predict task execution tokens, resulting in unauthorized task execution or access. Predictable guids could also lead to object collision or inference.
🔧 Fix: Replaced random.randint and random.choices with the cryptographically secure secrets module (secrets.randbelow and secrets.choice respectively) across helpers/guids.py, helpers/task_scheduler.py, api/scheduler_task_create.py, and tools/scheduler.py.
✅ Verification: Ensure the codebase correctly imports secrets and no longer relies on random for these sensitive values. Test the application execution to confirm task creation and guid generation remain functional.

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PR created automatically by Jules for task 7481684791568891228 started by @thirdeyenation

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