test(parser): bucket connection-reset preauth telemetry

[stacknil]

Summary

• bucket OpenSSH Connection reset by ... [preauth] unsupported lines under the existing sshd_connection_closed_preauth telemetry group
• add syslog and journalctl fixture coverage for the reset wording
• update parser quality expectations so the fixture contract stays explicit

Validation

• cmake --build build --config Debug --target test_parser
• ctest --test-dir build -C Debug -R parser --output-on-failure
• cmake --build build --config Debug
• ctest --test-dir build -C Debug --output-on-failure
• git diff --check

Safety

• Fixture additions use example-host and 203.0.113.x documentation addresses only.