Add configure_logging() (main.py): always logs to stderr, plus a rotating
file when PIRATS_LOG_FILE is set; level from PIRATS_LOG_LEVEL (default INFO).
Called from both the CLI entrypoint and the app lifespan (idempotent), which
also logs startup/migration/shutdown.
Targeted server-side events for ops/debugging (not every game event): game
created, player joined, player removed (kick/leave), game ended.
NixOS service: new logFile (/var/log/pirats/pirats.log) and logLevel options,
wired to the env vars; LogsDirectory=pirats makes the path writable under the
sandboxed DynamicUser. README documents the env vars/options.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
