feat: add scheduler and mail outbox

SMTP adapter with TLS and a fake, outbox with retries, backoff, rate limit and restart safety, scheduler tick with job-run records started by gunicorn, and a send_test_mail command.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N3t4WL7bd9bdHHNjEsxzqC

portal/tests/conftest.py

@@ -7,6 +7,7 @@ import pytest
 from portal.adapters import registry
 from portal.adapters.directory import FakeDirectory
 from portal.adapters.idp import FakeIdp
+from portal.adapters.mail import FakeMailer
 
 
 @pytest.fixture
@@ -28,14 +29,18 @@ def valid_env(tmp_path):
         "OIDC_CLIENT_ID": "portal-client",
         "OIDC_CLIENT_SECRET": "client-secret",
         "PUBLIC_BASE_URL": "https://portal.example.test",
+        "SMTP_HOST": "mail.example.test",
+        "SMTP_USERNAME": "portal@example.test",
+        "SMTP_PASSWORD": "mail-password",
+        "MAIL_FROM": "Portal <portal@example.test>",
     }
 
 
 @pytest.fixture(autouse=True)
 def adapters():
     """Fakes for every adapter, so no test can reach a real directory or provider."""
-    fakes = SimpleNamespace(directory=FakeDirectory(), idp=FakeIdp())
-    registry.install(fakes.directory, fakes.idp)
+    fakes = SimpleNamespace(directory=FakeDirectory(), idp=FakeIdp(), mailer=FakeMailer())
+    registry.install(fakes.directory, fakes.idp, fakes.mailer)
     yield fakes
     registry.install()