Replace hardcoded values across network, captcha, email, and cert
modules with BouncerConfig fields. All values have safe defaults
and are overridable in the [bouncer] section of the config file.
Configurable: probation_seconds, backoff_steps, nick_timeout,
rejoin_delay, http_timeout, captcha_poll_interval/timeout,
email_poll_interval/max_polls/request_timeout, cert_validity_days.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>