test: expand helper-module and SSH parsing coverage

[zeroth-blip]

Summary

This PR expands the unit-test suite with focused coverage for helper modules and SSH-related parsing paths.

Added coverage for

• ConfigServer::GetEthDev
• ConfigServer::Logger
• ConfigServer::LookupIP
• ConfigServer::Service
• ConfigServer::KillSSH
• ConfigServer::regexmain

Why this change

These areas are heavy on parsing, environment-dependent behavior, and guard logic, which makes them good candidates for focused regression coverage.

The new tests aim to:

• lock in current helper-module behavior
• exercise fallback and failure paths
• validate SSH log parsing across multiple real-world formats
• catch regressions earlier with fast unit-level feedback

What is included

• new unit tests for interface/address discovery and fallback handling
• logger coverage for file/syslog-oriented behavior
• lookup/service helper coverage
• targeted KillSSH behavior coverage
• deterministic regexmain coverage for SSH failure/accept flows and gating logic

What is not included

• no production code changes
• no workflow or smoke-test behavior changes

Validation

Ran locally and passed:

prove -v .github/tests/unit/getethdev.t \
  .github/tests/unit/logger.t \
  .github/tests/unit/lookupip.t \
  .github/tests/unit/service.t \
  .github/tests/unit/killssh.t \
  .github/tests/unit/regexmain.t

Result: PASS

Commits

• test: expand unit coverage for helper modules
• test: add killssh and regexmain coverage

[UptimeEnforcer]

@zeroth-blip I'm merging this.

In checkip.t, a very clean data-driven loop (assert_cases(&checkip, [ ... ])) is used for testing variations of IPs.
It would be really nice if you can generalize this across other scripts.