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>

events/bp/markets/services/markets.py

@@ -5,8 +5,9 @@ import unicodedata
 
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from shared.contracts.dtos import MarketPlaceDTO
-from shared.services.registry import services
+from shared.contracts.dtos import MarketPlaceDTO, PostDTO, dto_from_dict
+from shared.infrastructure.actions import call_action, ActionError
+from shared.infrastructure.data_client import fetch_data
 
 
 class MarketError(ValueError):
@@ -37,21 +38,33 @@ async def create_market(sess: AsyncSession, post_id: int, name: str) -> MarketPl
         raise MarketError("Market name must not be empty.")
     slug = slugify(name)
 
-    post = await services.blog.get_post_by_id(sess, post_id)
+    raw = await fetch_data("blog", "post-by-id", params={"id": post_id}, required=False)
+    post = dto_from_dict(PostDTO, raw) if raw else None
     if not post:
         raise MarketError(f"Post {post_id} does not exist.")
     if not post.is_page:
         raise MarketError("Markets can only be created on pages, not posts.")
 
     try:
-        return await services.market.create_marketplace(sess, "page", post_id, name, slug)
-    except ValueError as e:
+        result = await call_action("market", "create-marketplace", payload={
+            "container_type": "page", "container_id": post_id,
+            "name": name, "slug": slug,
+        })
+        return MarketPlaceDTO(**result)
+    except ActionError as e:
         raise MarketError(str(e)) from e
 
 
 async def soft_delete(sess: AsyncSession, post_slug: str, market_slug: str) -> bool:
-    post = await services.blog.get_post_by_slug(sess, post_slug)
+    raw = await fetch_data("blog", "post-by-slug", params={"slug": post_slug}, required=False)
+    post = dto_from_dict(PostDTO, raw) if raw else None
     if not post:
         return False
 
-    return await services.market.soft_delete_marketplace(sess, "page", post.id, market_slug)
+    try:
+        result = await call_action("market", "soft-delete-marketplace", payload={
+            "container_type": "page", "container_id": post.id, "slug": market_slug,
+        })
+        return result.get("deleted", False)
+    except ActionError:
+        return False