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/adapters/mail/fake.py

@@ -0,0 +1,24 @@
+"""In-memory mail server for tests (AD-1)."""
+
+from __future__ import annotations
+
+from .base import MailMessage, MailRejected, MailUnavailable
+
+
+class FakeMailer:
+    """Records what was sent. `unavailable` makes every send fail temporarily; recipients in
+    `rejected` are refused for good."""
+
+    def __init__(self) -> None:
+        self.sent: list[MailMessage] = []
+        self.unavailable = False
+        self.rejected: set[str] = set()
+        self.attempts = 0
+
+    def send(self, message: MailMessage) -> None:
+        self.attempts += 1
+        if self.unavailable:
+            raise MailUnavailable("The mail server is not available")
+        if message.recipient in self.rejected:
+            raise MailRejected("The mail server refused the message (550)")
+        self.sent.append(message)