Split cart into 4 microservices: relations, likes, orders, page-config→blog

Phase 1 - Relations service (internal): owns ContainerRelation, exposes
get-children data + attach/detach-child actions. Retargeted events, blog,
market callers from cart to relations.

Phase 2 - Likes service (internal): unified Like model replaces ProductLike
and PostLike with generic target_type/target_slug/target_id. Exposes
is-liked, liked-slugs, liked-ids data + toggle action.

Phase 3 - PageConfig → blog: moved ownership to blog with direct DB queries,
removed proxy endpoints from cart.

Phase 4 - Orders service (public): owns Order/OrderItem + SumUp checkout
flow. Cart checkout now delegates to orders via create-order action.
Webhook/return routes and reconciliation moved to orders.

Phase 5 - Infrastructure: docker-compose, deploy.sh, Dockerfiles updated
for all 3 new services. Added orders_url helper and factory model imports.

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

orders/bp/fragments/routes.py

@@ -0,0 +1,42 @@
+"""Orders app fragment endpoints.
+
+Fragments:
+  account-nav-item   "orders" link for account dashboard
+"""
+from __future__ import annotations
+
+from quart import Blueprint, Response, request
+from shared.infrastructure.fragments import FRAGMENT_HEADER
+
+
+def register():
+    bp = Blueprint("fragments", __name__, url_prefix="/internal/fragments")
+
+    async def _account_nav_item():
+        from shared.infrastructure.urls import orders_url
+        href = orders_url("/")
+        return (
+            '<div class="relative nav-group">'
+            f'<a href="{href}" class="justify-center cursor-pointer flex flex-row '
+            'items-center gap-2 rounded bg-stone-200 text-black p-3" data-hx-disable>'
+            'orders</a></div>'
+        )
+
+    _handlers = {
+        "account-nav-item": _account_nav_item,
+    }
+
+    @bp.before_request
+    async def _require_fragment_header():
+        if not request.headers.get(FRAGMENT_HEADER):
+            return Response("", status=403)
+
+    @bp.get("/<fragment_type>")
+    async def get_fragment(fragment_type: str):
+        handler = _handlers.get(fragment_type)
+        if handler is None:
+            return Response("", status=200, content_type="text/html")
+        html = await handler()
+        return Response(html, status=200, content_type="text/html")
+
+    return bp