Phase 5: Add order lifecycle, cart adoption glue services and handlers

- order_lifecycle.py: claim/confirm/get entries for order (cross-domain writes)
- cart_adoption.py: adopt anonymous cart+entries for logged-in user
- login_handlers.py: handle user.logged_in event for cart adoption
- order_handlers.py: placeholder handlers for order.created/paid events
- setup.py: register new handlers at startup

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

handlers/login_handlers.py

@@ -0,0 +1,15 @@
+from __future__ import annotations
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from shared.events import register_handler
+from shared.models.domain_event import DomainEvent
+from glue.services.cart_adoption import adopt_session_for_user
+
+
+async def on_user_logged_in(event: DomainEvent, session: AsyncSession) -> None:
+    payload = event.payload
+    await adopt_session_for_user(session, payload["user_id"], payload["session_id"])
+
+
+register_handler("user.logged_in", on_user_logged_in)

handlers/order_handlers.py

@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+import logging
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from shared.events import register_handler
+from shared.models.domain_event import DomainEvent
+
+log = logging.getLogger(__name__)
+
+
+async def on_order_created(event: DomainEvent, session: AsyncSession) -> None:
+    log.info("order.created: order_id=%s", event.payload.get("order_id"))
+
+
+async def on_order_paid(event: DomainEvent, session: AsyncSession) -> None:
+    log.info("order.paid: order_id=%s", event.payload.get("order_id"))
+
+
+register_handler("order.created", on_order_created)
+register_handler("order.paid", on_order_paid)