Spins up each service's server.py in a real subprocess via a free ephemeral
port (PORT env var), connects with real protocol clients, and asserts both
correct protocol behavior and RFC 5424 log output.
- 44 live tests across 10 services: http, ftp, smtp, redis, mqtt,
mysql, postgres, mongodb, pop3, imap
- Shared conftest.py: _ServiceProcess (bg reader thread + queue),
free_port, live_service fixture, assert_rfc5424 helper
- PORT env var added to all 10 targeted server.py templates
- New pytest marker `live`; excluded from default addopts run
- requirements-live-tests.txt: flask, twisted + protocol clients
