🛡️ Sentinel: [CRITICAL] Fix DoS vulnerability via massive integer conversion exhaustion

[ManupaKDU]

🚨 Severity: CRITICAL
💡 Vulnerability: Denial of Service (DoS) via Application Crash.
Python 3.11+ limits integer-to-string conversions (e.g., calling repr() or string formatting on massive ints) via sys.set_int_max_str_digits (default 4300 digits). If an attacker passed massive integers (e.g., 10**100000) as the ip or timeout arguments, the downstream string formatting and repr() logging would fail with an unhandled ValueError. This unhandled exception bubbles up and crashes the worker thread pool in concurrent.futures, leading to a complete Denial of Service.
🎯 Impact: An attacker or misconfigured client passing massive integer values could immediately crash the entire background scanning pool, halting all network scanning operations.
🔧 Fix:

1. Added explicit bound checks on timeout and ip when they are of type int to reject massive inputs immediately.
2. Wrapped all repr() calls within logging except blocks in a try...except ValueError to catch any remaining integer conversion limits and provide a safe <unrepresentable> fallback string.
3. Added robust unit tests in test_testping1.py covering massive ints for both parameters and a malicious __repr__ object.
   ✅ Verification: Ran python3 -m unittest test_testping1.py successfully. Verified temporary testing files were removed.

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PR created automatically by Jules for task 8003572088896931687 started by @ManupaKDU

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