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>

likes/bp/data/routes.py

@@ -1,109 +1,14 @@
-"""Likes app data endpoints."""
+"""Likes app data endpoints.
+
+All queries are defined in ``likes/queries.sx``.
+"""
 from __future__ import annotations
 
-from quart import Blueprint, g, jsonify, request
+from quart import Blueprint
 
-from shared.infrastructure.data_client import DATA_HEADER
+from shared.infrastructure.query_blueprint import create_data_blueprint
 
 
 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
-        from shared.infrastructure.internal_auth import validate_internal_request
-        if not validate_internal_request():
-            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)
-
-    # --- is-liked ---
-    async def _is_liked():
-        """Check if a user has liked a specific target."""
-        from sqlalchemy import select
-        from models.like import Like
-
-        user_id = request.args.get("user_id", type=int)
-        target_type = request.args.get("target_type", "")
-        target_slug = request.args.get("target_slug")
-        target_id = request.args.get("target_id", type=int)
-
-        if not user_id or not target_type:
-            return {"liked": False}
-
-        filters = [
-            Like.user_id == user_id,
-            Like.target_type == target_type,
-            Like.deleted_at.is_(None),
-        ]
-        if target_slug is not None:
-            filters.append(Like.target_slug == target_slug)
-        elif target_id is not None:
-            filters.append(Like.target_id == target_id)
-        else:
-            return {"liked": False}
-
-        row = await g.s.scalar(select(Like.id).where(*filters))
-        return {"liked": row is not None}
-
-    _handlers["is-liked"] = _is_liked
-
-    # --- liked-slugs ---
-    async def _liked_slugs():
-        """Return all liked target_slugs for a user + target_type."""
-        from sqlalchemy import select
-        from models.like import Like
-
-        user_id = request.args.get("user_id", type=int)
-        target_type = request.args.get("target_type", "")
-
-        if not user_id or not target_type:
-            return []
-
-        result = await g.s.execute(
-            select(Like.target_slug).where(
-                Like.user_id == user_id,
-                Like.target_type == target_type,
-                Like.target_slug.isnot(None),
-                Like.deleted_at.is_(None),
-            )
-        )
-        return list(result.scalars().all())
-
-    _handlers["liked-slugs"] = _liked_slugs
-
-    # --- liked-ids ---
-    async def _liked_ids():
-        """Return all liked target_ids for a user + target_type."""
-        from sqlalchemy import select
-        from models.like import Like
-
-        user_id = request.args.get("user_id", type=int)
-        target_type = request.args.get("target_type", "")
-
-        if not user_id or not target_type:
-            return []
-
-        result = await g.s.execute(
-            select(Like.target_id).where(
-                Like.user_id == user_id,
-                Like.target_type == target_type,
-                Like.target_id.isnot(None),
-                Like.deleted_at.is_(None),
-            )
-        )
-        return list(result.scalars().all())
-
-    _handlers["liked-ids"] = _liked_ids
-
+    bp, _handlers = create_data_blueprint("likes")
     return bp