feat: make all operational constants configurable via bouncer.toml

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>

tests/test_config.py

@@ -123,3 +123,58 @@ tls = true
 """
         cfg = load(_write_config(config))
         assert cfg.networks["test"].port == 6697
+
+    def test_operational_defaults(self):
+        """Ensure all operational values have sane defaults."""
+        cfg = load(_write_config(MINIMAL_CONFIG))
+        b = cfg.bouncer
+        assert b.probation_seconds == 45
+        assert b.backoff_steps == [5, 10, 30, 60, 120, 300]
+        assert b.nick_timeout == 10
+        assert b.rejoin_delay == 3
+        assert b.http_timeout == 15
+        assert b.captcha_api_key == ""
+        assert b.captcha_poll_interval == 3
+        assert b.captcha_poll_timeout == 120
+        assert b.email_poll_interval == 15
+        assert b.email_max_polls == 30
+        assert b.email_request_timeout == 20
+        assert b.cert_validity_days == 3650
+
+    def test_operational_overrides(self):
+        """Configurable operational values are parsed from TOML."""
+        config = """\
+[bouncer]
+password = "x"
+probation_seconds = 60
+backoff_steps = [10, 30, 90]
+nick_timeout = 20
+rejoin_delay = 5
+http_timeout = 30
+captcha_api_key = "test-key"
+captcha_poll_interval = 5
+captcha_poll_timeout = 60
+email_poll_interval = 10
+email_max_polls = 20
+email_request_timeout = 25
+cert_validity_days = 365
+
+[proxy]
+
+[networks.test]
+host = "irc.example.com"
+"""
+        cfg = load(_write_config(config))
+        b = cfg.bouncer
+        assert b.probation_seconds == 60
+        assert b.backoff_steps == [10, 30, 90]
+        assert b.nick_timeout == 20
+        assert b.rejoin_delay == 5
+        assert b.http_timeout == 30
+        assert b.captcha_api_key == "test-key"
+        assert b.captcha_poll_interval == 5
+        assert b.captcha_poll_timeout == 60
+        assert b.email_poll_interval == 10
+        assert b.email_max_polls == 20
+        assert b.email_request_timeout == 25
+        assert b.cert_validity_days == 365