Domain isolation: replace cross-domain imports with service calls

Replace direct Post, MarketPlace, Calendar model queries and HTTP API
calls with typed service calls. Events registers all 4 services via
domain_services_fn with has() guards.

Key changes:
- app.py: use domain_services_fn, Post/Calendar/MarketPlace queries
  → services.blog/calendar/market, HTTP cart API → services.cart
- calendars/markets services: Post → services.blog
- post_associations: Post → services.blog, direct queries → services
- markets routes: remove unused MarketPlace import
- glue imports → shared imports throughout

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

app.py

@@ -5,7 +5,6 @@ from pathlib import Path
 
 from quart import g, abort
 from jinja2 import FileSystemLoader, ChoiceLoader
-from sqlalchemy import select
 
 from shared.infrastructure.factory import create_base_app
 
@@ -17,34 +16,36 @@ async def events_context() -> dict:
     Events app context processor.
 
     - menu_items: direct DB query via glue layer
-    - cart_count/cart_total: fetched from cart internal API
+    - cart_count/cart_total: via cart service (shared DB)
     """
     from shared.infrastructure.context import base_context
-    from glue.services.navigation import get_navigation_tree
-    from shared.infrastructure.internal_api import get as api_get
+    from shared.services.navigation import get_navigation_tree
+    from shared.services.registry import services
+    from shared.infrastructure.cart_identity import current_cart_identity
 
     ctx = await base_context()
 
     ctx["menu_items"] = await get_navigation_tree(g.s)
 
-    # Cart data from cart API (includes both product + calendar counts)
-    cart_data = await api_get("cart", "/internal/cart/summary", forward_session=True)
-    if cart_data:
-        ctx["cart_count"] = cart_data.get("count", 0) + cart_data.get("calendar_count", 0)
-        ctx["cart_total"] = cart_data.get("total", 0) + cart_data.get("calendar_total", 0)
-    else:
-        ctx["cart_count"] = 0
-        ctx["cart_total"] = 0
+    # Cart data via service (replaces cross-app HTTP API)
+    ident = current_cart_identity()
+    summary = await services.cart.cart_summary(
+        g.s, user_id=ident["user_id"], session_id=ident["session_id"],
+    )
+    ctx["cart_count"] = summary.count + summary.calendar_count
+    ctx["cart_total"] = float(summary.total + summary.calendar_total)
 
     return ctx
 
 
 def create_app() -> "Quart":
-    from shared.models.ghost_content import Post
-    from models.calendars import Calendar
-    from shared.models.market_place import MarketPlace
+    from services import register_domain_services
 
-    app = create_base_app("events", context_fn=events_context)
+    app = create_base_app(
+        "events",
+        context_fn=events_context,
+        domain_services_fn=register_domain_services,
+    )
 
     # App-specific templates override shared templates
     app_templates = str(Path(__file__).resolve().parent / "templates")
@@ -90,11 +91,7 @@ def create_app() -> "Quart":
         slug = getattr(g, "post_slug", None)
         if not slug:
             return
-        post = (
-            await g.s.execute(
-                select(Post).where(Post.slug == slug)
-            )
-        ).scalar_one_or_none()
+        post = await services.blog.get_post_by_slug(g.s, slug)
         if not post:
             abort(404)
         g.post_data = {
@@ -114,20 +111,8 @@ def create_app() -> "Quart":
         if not post_data:
             return {}
         post_id = post_data["post"]["id"]
-        calendars = (
-            await g.s.execute(
-                select(Calendar)
-                .where(Calendar.container_type == "page", Calendar.container_id == post_id, Calendar.deleted_at.is_(None))
-                .order_by(Calendar.name.asc())
-            )
-        ).scalars().all()
-        markets = (
-            await g.s.execute(
-                select(MarketPlace)
-                .where(MarketPlace.container_type == "page", MarketPlace.container_id == post_id, MarketPlace.deleted_at.is_(None))
-                .order_by(MarketPlace.name.asc())
-            )
-        ).scalars().all()
+        calendars = await services.calendar.calendars_for_container(g.s, "page", post_id)
+        markets = await services.market.marketplaces_for_container(g.s, "page", post_id)
         return {
             **post_data,
             "calendars": calendars,