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>

blog/bp/post/admin/routes.py

@@ -193,7 +193,8 @@ def register():
     """Show calendar month view for browsing entries"""
     from shared.models.calendars import Calendar
     from shared.utils.calendar_helpers import parse_int_arg, add_months, build_calendar_weeks
-    from shared.services.registry import services
+    from shared.infrastructure.data_client import fetch_data
+    from shared.contracts.dtos import CalendarEntryDTO, dto_from_dict
     from sqlalchemy import select
     from datetime import datetime, timezone
     import calendar as pycalendar
@@ -228,7 +229,7 @@ def register():
     month_name = pycalendar.month_name[month]
     weekday_names = [pycalendar.day_abbr[i] for i in range(7)]
 
-    # Get entries for this month
+    # Get entries for this month via events data endpoint
     period_start = datetime(year, month, 1, tzinfo=timezone.utc)
     next_y, next_m = add_months(year, month, +1)
     period_end = datetime(next_y, next_m, 1, tzinfo=timezone.utc)
@@ -238,10 +239,15 @@ def register():
     is_admin = bool(user and getattr(user, "is_admin", False))
     session_id = qsession.get("calendar_sid")
 
-    month_entries = await services.calendar.visible_entries_for_period(
-      g.s, calendar_obj.id, period_start, period_end,
-      user_id=user_id, is_admin=is_admin, session_id=session_id,
-    )
+    raw_entries = await fetch_data("events", "visible-entries-for-period", params={
+        "calendar_id": calendar_obj.id,
+        "period_start": period_start.isoformat(),
+        "period_end": period_end.isoformat(),
+        "user_id": user_id,
+        "is_admin": str(is_admin).lower(),
+        "session_id": session_id,
+    }, required=False) or []
+    month_entries = [dto_from_dict(CalendarEntryDTO, e) for e in raw_entries]
 
     # Get associated entry IDs for this post
     post_id = g.post_data["post"]["id"]
@@ -609,18 +615,24 @@ def register():
     return redirect(redirect_url)
 
 
+  async def _fetch_page_markets(post_id):
+    """Fetch marketplaces for a page via market data endpoint."""
+    from shared.infrastructure.data_client import fetch_data
+    from shared.contracts.dtos import MarketPlaceDTO, dto_from_dict
+    raw = await fetch_data("market", "marketplaces-for-container",
+                           params={"type": "page", "id": post_id}, required=False) or []
+    return [dto_from_dict(MarketPlaceDTO, m) for m in raw]
+
   @bp.get("/markets/")
   @require_admin
   async def markets(slug: str):
     """List markets for this page."""
-    from shared.services.registry import services
-
     post = (g.post_data or {}).get("post", {})
     post_id = post.get("id")
     if not post_id:
         return await make_response("Post not found", 404)
 
-    page_markets = await services.market.marketplaces_for_container(g.s, "page", post_id)
+    page_markets = await _fetch_page_markets(post_id)
 
     html = await render_template(
         "_types/post/admin/_markets_panel.html",
@@ -634,7 +646,6 @@ def register():
   async def create_market(slug: str):
     """Create a new market for this page."""
     from ..services.markets import create_market as _create_market, MarketError
-    from shared.services.registry import services
     from quart import jsonify
 
     post = (g.post_data or {}).get("post", {})
@@ -651,7 +662,7 @@ def register():
         return jsonify({"error": str(e)}), 400
 
     # Return updated markets list
-    page_markets = await services.market.marketplaces_for_container(g.s, "page", post_id)
+    page_markets = await _fetch_page_markets(post_id)
 
     html = await render_template(
         "_types/post/admin/_markets_panel.html",
@@ -665,7 +676,6 @@ def register():
   async def delete_market(slug: str, market_slug: str):
     """Soft-delete a market."""
     from ..services.markets import soft_delete_market
-    from shared.services.registry import services
     from quart import jsonify
 
     post = (g.post_data or {}).get("post", {})
@@ -676,7 +686,7 @@ def register():
         return jsonify({"error": "Market not found"}), 404
 
     # Return updated markets list
-    page_markets = await services.market.marketplaces_for_container(g.s, "page", post_id)
+    page_markets = await _fetch_page_markets(post_id)
 
     html = await render_template(
         "_types/post/admin/_markets_panel.html",