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>

services/cart_adoption.py

@@ -0,0 +1,50 @@
+"""Glue service: adopt anonymous cart items + calendar entries for a logged-in user."""
+from __future__ import annotations
+
+from sqlalchemy import select, update, func
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from market.models.market import CartItem
+from events.models.calendars import CalendarEntry
+
+
+async def adopt_session_for_user(
+    session: AsyncSession,
+    user_id: int,
+    session_id: str,
+) -> None:
+    """Adopt anonymous cart items + calendar entries for a logged-in user."""
+    # --- adopt cart items ---
+    anon_result = await session.execute(
+        select(CartItem).where(
+            CartItem.deleted_at.is_(None),
+            CartItem.user_id.is_(None),
+            CartItem.session_id == session_id,
+        )
+    )
+    anon_items = anon_result.scalars().all()
+
+    if anon_items:
+        # Soft-delete existing user cart
+        await session.execute(
+            update(CartItem)
+            .where(CartItem.deleted_at.is_(None), CartItem.user_id == user_id)
+            .values(deleted_at=func.now())
+        )
+        for ci in anon_items:
+            ci.user_id = user_id
+
+    # --- adopt calendar entries ---
+    await session.execute(
+        update(CalendarEntry)
+        .where(CalendarEntry.deleted_at.is_(None), CalendarEntry.user_id == user_id)
+        .values(deleted_at=func.now())
+    )
+    cal_result = await session.execute(
+        select(CalendarEntry).where(
+            CalendarEntry.deleted_at.is_(None),
+            CalendarEntry.session_id == session_id,
+        )
+    )
+    for entry in cal_result.scalars().all():
+        entry.user_id = user_id