test(detectors): add comprehensive integration tests for YAML detectors

Add 5 integration tests covering:
- Basic YAML detector loading and registration
- Event generation with field extraction (data.*, workload.*)
- 2-level detector chaining/composition
- Data filter application (matching/non-matching)
- Error handling (invalid YAML, missing fields)

Tests follow existing integration test patterns with proper cleanup,
goleak checking, and clear logging for debugging.

Author: yanivagman