Add unit tests for pattern matching

[bad-antics]

Description

LogReaper currently has zero automated tests. We need a basic test suite that validates the regex pattern matching engine against known log samples.

Details

• Create a tests/ directory with sample log files (sanitized/synthetic)
• Write a test runner (shell script or C test harness)
• Test cases needed:
  • SSH brute force detection in auth.log samples
  • SQL injection detection in Apache/Nginx access logs
  • Privilege escalation pattern matching
  • IOC extraction (IPs, domains, hashes)
  • False positive verification (benign log lines that should NOT trigger alerts)
• Add a make test target to the Makefile
• Integrate with CI workflow

Acceptance Criteria

• make test runs and passes
• At least 10 test cases covering major detection categories
• CI runs tests on every push/PR
• Test log samples contain no real/sensitive data