Replace inter-service _handlers dicts with declarative sx defquery/defaction

The inter-service data layer (fetch_data/call_action) was the least
structured part of the codebase — Python _handlers dicts with ad-hoc
param extraction scattered across 16 route files. This replaces them
with declarative .sx query/action definitions that make the entire
inter-service protocol self-describing and greppable.

Infrastructure:
- defquery/defaction special forms in the sx evaluator
- Query/action registry with load, lookup, and schema introspection
- Query executor using async_eval with I/O primitives
- Blueprint factories (create_data_blueprint/create_action_blueprint)
  with sx-first dispatch and Python fallback
- /internal/schema endpoint on every service
- parse-datetime and split-ids primitives for type coercion

Service extractions:
- LikesService (toggle, is_liked, liked_slugs, liked_ids)
- PageConfigService (ensure, get_by_container, get_by_id, get_batch, update)
- RelationsService (wraps module-level functions)
- AccountDataService (user_by_email, newsletters)
- CartItemsService, MarketDataService (raw SQLAlchemy lookups)

50 of 54 handlers converted to sx, 4 Python fallbacks remain
(ghost-sync/push-member, clear-cart-for-order, create-order).
Net: -1,383 lines Python, +251 lines modified.

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

market/bp/actions/routes.py

@@ -1,74 +1,14 @@
 """Market app action endpoints.
 
-Exposes write operations at ``/internal/actions/<action_name>`` for
-cross-app callers (blog, events) via the internal action client.
+All actions are defined in ``market/actions.sx``.
 """
 from __future__ import annotations
 
-from quart import Blueprint, g, jsonify, request
+from quart import Blueprint
 
-from shared.infrastructure.actions import ACTION_HEADER
-from shared.services.registry import services
+from shared.infrastructure.query_blueprint import create_action_blueprint
 
 
 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
-        from shared.infrastructure.internal_auth import validate_internal_request
-        if not validate_internal_request():
-            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
-        try:
-            result = await handler()
-            return jsonify(result)
-        except Exception as exc:
-            import logging
-            logging.getLogger(__name__).exception("Action %s failed", action_name)
-            return jsonify({"error": str(exc)}), 500
-
-    # --- 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
-
+    bp, _handlers = create_action_blueprint("market")
     return bp