Add Phase 1 MVP: D&D text-adventure server

FastAPI + Postgres backend with fastapi-users auth, games/characters
CRUD, and a WebSocket chat endpoint where an x.ai Grok DM narrates
play, rolls dice, and maintains character sheets via tool calls.
React + Tailwind frontend covers registration/login, game list and
creation, participation-code join flow, character viewer, and a
real-time chat session view. Docker Compose skeleton (Postgres +
backend) included; Caddy/frontend container wiring is deferred to
the deploy milestone.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/app/auth/email.py

@@ -0,0 +1,30 @@
+import logging
+
+import aiosmtplib
+from email.message import EmailMessage
+
+from app.config import settings
+
+logger = logging.getLogger("app.auth.email")
+
+
+async def send_email(to: str, subject: str, body: str) -> None:
+    """Send a plaintext email, or log it to the console if no SMTP server is configured (dev mode)."""
+    if not settings.smtp_host:
+        logger.info("=== DEV EMAIL (no SMTP configured) ===\nTo: %s\nSubject: %s\n\n%s", to, subject, body)
+        return
+
+    message = EmailMessage()
+    message["From"] = settings.smtp_from
+    message["To"] = to
+    message["Subject"] = subject
+    message.set_content(body)
+
+    await aiosmtplib.send(
+        message,
+        hostname=settings.smtp_host,
+        port=settings.smtp_port,
+        username=settings.smtp_user or None,
+        password=settings.smtp_password or None,
+        start_tls=True,
+    )