Decouple all cross-app service calls to HTTP endpoints

Replace every direct cross-app services.* call with HTTP-based
communication: call_action() for writes, fetch_data() for reads.
Each app now registers only its own domain service.

Infrastructure:
- shared/infrastructure/actions.py — POST client for /internal/actions/
- shared/infrastructure/data_client.py — GET client for /internal/data/
- shared/contracts/dtos.py — dto_to_dict/dto_from_dict serialization

Action endpoints (writes):
- events: 8 handlers (ticket adjust, claim/confirm, toggle, adopt)
- market: 2 handlers (create/soft-delete marketplace)
- cart: 1 handler (adopt cart for user)

Data endpoints (reads):
- blog: 4 (post-by-slug/id, posts-by-ids, search-posts)
- events: 10 (pending entries/tickets, entries/tickets for page/order,
  entry-ids, associated-entries, calendars, visible-entries-for-period)
- market: 1 (marketplaces-for-container)
- cart: 1 (cart-summary)

Service registration cleanup:
- blog→blog+federation, events→calendar+federation,
  market→market+federation, cart→cart only,
  federation→federation only, account→nothing
- Stubs reduced to minimal StubFederationService

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

cart/bp/cart/services/calendar_cart.py

@@ -2,7 +2,8 @@ from __future__ import annotations
 
 from decimal import Decimal
 
-from shared.services.registry import services
+from shared.infrastructure.data_client import fetch_data
+from shared.contracts.dtos import CalendarEntryDTO, TicketDTO, dto_from_dict
 from .identity import current_cart_identity
 
 
@@ -12,11 +13,13 @@ async def get_calendar_cart_entries(session):
     current cart identity (user or anonymous session).
     """
     ident = current_cart_identity()
-    return await services.calendar.pending_entries(
-        session,
-        user_id=ident["user_id"],
-        session_id=ident["session_id"],
-    )
+    params = {}
+    if ident["user_id"] is not None:
+        params["user_id"] = ident["user_id"]
+    if ident["session_id"] is not None:
+        params["session_id"] = ident["session_id"]
+    raw = await fetch_data("events", "pending-entries", params=params, required=False) or []
+    return [dto_from_dict(CalendarEntryDTO, e) for e in raw]
 
 
 def calendar_total(entries) -> Decimal:
@@ -33,11 +36,13 @@ def calendar_total(entries) -> Decimal:
 async def get_ticket_cart_entries(session):
     """Return all reserved tickets (as TicketDTOs) for the current identity."""
     ident = current_cart_identity()
-    return await services.calendar.pending_tickets(
-        session,
-        user_id=ident["user_id"],
-        session_id=ident["session_id"],
-    )
+    params = {}
+    if ident["user_id"] is not None:
+        params["user_id"] = ident["user_id"]
+    if ident["session_id"] is not None:
+        params["session_id"] = ident["session_id"]
+    raw = await fetch_data("events", "pending-tickets", params=params, required=False) or []
+    return [dto_from_dict(TicketDTO, t) for t in raw]
 
 
 def ticket_total(tickets) -> Decimal:

cart/bp/cart/services/check_sumup_status.py

@@ -1,6 +1,6 @@
 from shared.browser.app.payments.sumup import get_checkout as sumup_get_checkout
 from shared.events import emit_activity
-from shared.services.registry import services
+from shared.infrastructure.actions import call_action
 from .clear_cart_for_order import clear_cart_for_order
 
 
@@ -14,10 +14,13 @@ async def check_sumup_status(session, order):
     if sumup_status == "PAID":
         if order.status != "paid":
             order.status = "paid"
-            await services.calendar.confirm_entries_for_order(
-                session, order.id, order.user_id, order.session_id
-            )
-            await services.calendar.confirm_tickets_for_order(session, order.id)
+            await call_action("events", "confirm-entries-for-order", payload={
+                "order_id": order.id, "user_id": order.user_id,
+                "session_id": order.session_id,
+            })
+            await call_action("events", "confirm-tickets-for-order", payload={
+                "order_id": order.id,
+            })
 
             # Clear cart only after payment is confirmed
             page_post_id = page_config.container_id if page_config else None

cart/bp/cart/services/checkout.py

@@ -14,7 +14,7 @@ from shared.models.market_place import MarketPlace
 from shared.config import config
 from shared.contracts.dtos import CalendarEntryDTO
 from shared.events import emit_activity
-from shared.services.registry import services
+from shared.infrastructure.actions import call_action
 
 
 async def find_or_create_cart_item(
@@ -156,15 +156,17 @@ async def create_order_from_cart(
         )
         session.add(oi)
 
-    # Mark pending calendar entries as "ordered" via calendar service
-    await services.calendar.claim_entries_for_order(
-        session, order.id, user_id, session_id, page_post_id
-    )
+    # Mark pending calendar entries as "ordered" via events action endpoint
+    await call_action("events", "claim-entries-for-order", payload={
+        "order_id": order.id, "user_id": user_id,
+        "session_id": session_id, "page_post_id": page_post_id,
+    })
 
     # Claim reserved tickets for this order
-    await services.calendar.claim_tickets_for_order(
-        session, order.id, user_id, session_id, page_post_id
-    )
+    await call_action("events", "claim-tickets-for-order", payload={
+        "order_id": order.id, "user_id": user_id,
+        "session_id": session_id, "page_post_id": page_post_id,
+    })
 
     await emit_activity(
         session,

cart/bp/cart/services/page_cart.py

@@ -15,7 +15,8 @@ from sqlalchemy.orm import selectinload
 from shared.models.market import CartItem
 from shared.models.market_place import MarketPlace
 from shared.models.page_config import PageConfig
-from shared.services.registry import services
+from shared.infrastructure.data_client import fetch_data
+from shared.contracts.dtos import CalendarEntryDTO, TicketDTO, PostDTO, dto_from_dict
 from .identity import current_cart_identity
 
 
@@ -50,21 +51,25 @@ async def get_cart_for_page(session, post_id: int) -> list[CartItem]:
 async def get_calendar_entries_for_page(session, post_id: int):
     """Return pending calendar entries (DTOs) scoped to a specific page."""
     ident = current_cart_identity()
-    return await services.calendar.entries_for_page(
-        session, post_id,
-        user_id=ident["user_id"],
-        session_id=ident["session_id"],
-    )
+    params = {"page_id": post_id}
+    if ident["user_id"] is not None:
+        params["user_id"] = ident["user_id"]
+    if ident["session_id"] is not None:
+        params["session_id"] = ident["session_id"]
+    raw = await fetch_data("events", "entries-for-page", params=params, required=False) or []
+    return [dto_from_dict(CalendarEntryDTO, e) for e in raw]
 
 
 async def get_tickets_for_page(session, post_id: int):
     """Return reserved tickets (DTOs) scoped to a specific page."""
     ident = current_cart_identity()
-    return await services.calendar.tickets_for_page(
-        session, post_id,
-        user_id=ident["user_id"],
-        session_id=ident["session_id"],
-    )
+    params = {"page_id": post_id}
+    if ident["user_id"] is not None:
+        params["user_id"] = ident["user_id"]
+    if ident["session_id"] is not None:
+        params["session_id"] = ident["session_id"]
+    raw = await fetch_data("events", "tickets-for-page", params=params, required=False) or []
+    return [dto_from_dict(TicketDTO, t) for t in raw]
 
 
 async def get_cart_grouped_by_page(session) -> list[dict]:
@@ -167,7 +172,11 @@ async def get_cart_grouped_by_page(session) -> list[dict]:
     configs_by_post: dict[int, PageConfig] = {}
 
     if post_ids:
-        for p in await services.blog.get_posts_by_ids(session, post_ids):
+        raw_posts = await fetch_data("blog", "posts-by-ids",
+                                     params={"ids": ",".join(str(i) for i in post_ids)},
+                                     required=False) or []
+        for raw_p in raw_posts:
+            p = dto_from_dict(PostDTO, raw_p)
             posts_by_id[p.id] = p
 
         pc_result = await session.execute(