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>

market/bp/__init__.py

@@ -3,3 +3,5 @@ from .product.routes import register as register_product
 from .all_markets.routes import register as register_all_markets
 from .page_markets.routes import register as register_page_markets
 from .fragments import register_fragments
+from .actions import register_actions
+from .data import register_data

market/bp/actions/__init__.py

@@ -0,0 +1 @@
+from .routes import register as register_actions

market/bp/actions/routes.py

@@ -0,0 +1,66 @@
+"""Market app action endpoints.
+
+Exposes write operations at ``/internal/actions/<action_name>`` for
+cross-app callers (blog, events) via the internal action client.
+"""
+from __future__ import annotations
+
+from quart import Blueprint, g, jsonify, request
+
+from shared.infrastructure.actions import ACTION_HEADER
+from shared.services.registry import services
+
+
+def register() -> Blueprint:
+    bp = Blueprint("actions", __name__, url_prefix="/internal/actions")
+
+    @bp.before_request
+    async def _require_action_header():
+        if not request.headers.get(ACTION_HEADER):
+            return jsonify({"error": "forbidden"}), 403
+
+    _handlers: dict[str, object] = {}
+
+    @bp.post("/<action_name>")
+    async def handle_action(action_name: str):
+        handler = _handlers.get(action_name)
+        if handler is None:
+            return jsonify({"error": "unknown action"}), 404
+        result = await handler()
+        return jsonify(result)
+
+    # --- create-marketplace ---
+    async def _create_marketplace():
+        data = await request.get_json()
+        mp = await services.market.create_marketplace(
+            g.s,
+            data["container_type"],
+            data["container_id"],
+            data["name"],
+            data["slug"],
+        )
+        return {
+            "id": mp.id,
+            "container_type": mp.container_type,
+            "container_id": mp.container_id,
+            "name": mp.name,
+            "slug": mp.slug,
+            "description": mp.description,
+        }
+
+    _handlers["create-marketplace"] = _create_marketplace
+
+    # --- soft-delete-marketplace ---
+    async def _soft_delete_marketplace():
+        data = await request.get_json()
+        deleted = await services.market.soft_delete_marketplace(
+            g.s,
+            data["container_type"],
+            data["container_id"],
+            data["slug"],
+        )
+        return {"deleted": deleted}
+
+    _handlers["soft-delete-marketplace"] = _soft_delete_marketplace
+
+    return bp

market/bp/all_markets/routes.py

@@ -12,6 +12,8 @@ from __future__ import annotations
 from quart import Blueprint, g, request, render_template, make_response
 
 from shared.browser.app.utils.htmx import is_htmx_request
+from shared.infrastructure.data_client import fetch_data
+from shared.contracts.dtos import PostDTO, dto_from_dict
 from shared.services.registry import services
 
 
@@ -32,8 +34,11 @@ def register() -> Blueprint:
                 if m.container_type == "page"
             })
             if post_ids:
-                posts = await services.blog.get_posts_by_ids(g.s, post_ids)
-                for p in posts:
+                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)
                     page_info[p.id] = {"title": p.title, "slug": p.slug}
 
         return markets, has_more, page_info

market/bp/data/__init__.py

@@ -0,0 +1 @@
+from .routes import register as register_data

market/bp/data/routes.py

@@ -0,0 +1,44 @@
+"""Market app data endpoints.
+
+Exposes read-only JSON queries at ``/internal/data/<query_name>`` for
+cross-app callers via the internal data client.
+"""
+from __future__ import annotations
+
+from quart import Blueprint, g, jsonify, request
+
+from shared.infrastructure.data_client import DATA_HEADER
+from shared.contracts.dtos import dto_to_dict
+from shared.services.registry import services
+
+
+def register() -> Blueprint:
+    bp = Blueprint("data", __name__, url_prefix="/internal/data")
+
+    @bp.before_request
+    async def _require_data_header():
+        if not request.headers.get(DATA_HEADER):
+            return jsonify({"error": "forbidden"}), 403
+
+    _handlers: dict[str, object] = {}
+
+    @bp.get("/<query_name>")
+    async def handle_query(query_name: str):
+        handler = _handlers.get(query_name)
+        if handler is None:
+            return jsonify({"error": "unknown query"}), 404
+        result = await handler()
+        return jsonify(result)
+
+    # --- marketplaces-for-container ---
+    async def _marketplaces_for_container():
+        container_type = request.args.get("type", "")
+        container_id = request.args.get("id", type=int)
+        markets = await services.market.marketplaces_for_container(
+            g.s, container_type, container_id,
+        )
+        return [dto_to_dict(m) for m in markets]
+
+    _handlers["marketplaces-for-container"] = _marketplaces_for_container
+
+    return bp