Eliminate Python page helpers from account, federation, and cart

All three services now fetch page data via (service ...) IO primitives
in .sx defpages instead of Python middleman functions.

- Account: newsletters-data → AccountPageService.newsletters_data
- Federation: 8 page helpers → FederationPageService methods
  (timeline, compose, search, following, followers, notifications)
- Cart: 4 page helpers → CartPageService methods
  (overview, page-cart, admin, payments)
- Serializers moved to service modules, thin delegates kept for routes
- ~520 lines of Python page helpers removed

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

cart/services/__init__.py

@@ -12,3 +12,6 @@ def register_domain_services() -> None:
     from shared.services.cart_impl import SqlCartService
 
     services.cart = SqlCartService()
+
+    from .cart_page import CartPageService
+    services.register("cart_page", CartPageService())

cart/services/cart_page.py

@@ -0,0 +1,187 @@
+"""Cart page data service — provides serialized dicts for .sx defpages."""
+from __future__ import annotations
+
+from typing import Any
+
+
+def _serialize_cart_item(item: Any) -> dict:
+    from quart import url_for
+    from shared.infrastructure.urls import market_product_url
+
+    p = item.product if hasattr(item, "product") else item
+    slug = p.slug if hasattr(p, "slug") else ""
+    unit_price = getattr(p, "special_price", None) or getattr(p, "regular_price", None)
+    currency = getattr(p, "regular_price_currency", "GBP") or "GBP"
+    return {
+        "slug": slug,
+        "title": p.title if hasattr(p, "title") else "",
+        "image": p.image if hasattr(p, "image") else None,
+        "brand": getattr(p, "brand", None),
+        "is_deleted": getattr(item, "is_deleted", False),
+        "unit_price": float(unit_price) if unit_price else None,
+        "special_price": float(p.special_price) if getattr(p, "special_price", None) else None,
+        "regular_price": float(p.regular_price) if getattr(p, "regular_price", None) else None,
+        "currency": currency,
+        "quantity": item.quantity,
+        "product_id": p.id,
+        "product_url": market_product_url(slug),
+        "qty_url": url_for("cart_global.update_quantity", product_id=p.id),
+    }
+
+
+def _serialize_cal_entry(e: Any) -> dict:
+    name = getattr(e, "name", None) or getattr(e, "calendar_name", "")
+    start = e.start_at if hasattr(e, "start_at") else ""
+    end = getattr(e, "end_at", None)
+    cost = getattr(e, "cost", 0) or 0
+    end_str = f" \u2013 {end}" if end else ""
+    return {
+        "name": name,
+        "date_str": f"{start}{end_str}",
+        "cost": float(cost),
+    }
+
+
+def _serialize_ticket_group(tg: Any) -> dict:
+    name = tg.entry_name if hasattr(tg, "entry_name") else tg.get("entry_name", "")
+    tt_name = tg.ticket_type_name if hasattr(tg, "ticket_type_name") else tg.get("ticket_type_name", "")
+    price = tg.price if hasattr(tg, "price") else tg.get("price", 0)
+    quantity = tg.quantity if hasattr(tg, "quantity") else tg.get("quantity", 0)
+    line_total = tg.line_total if hasattr(tg, "line_total") else tg.get("line_total", 0)
+    entry_id = tg.entry_id if hasattr(tg, "entry_id") else tg.get("entry_id", "")
+    tt_id = tg.ticket_type_id if hasattr(tg, "ticket_type_id") else tg.get("ticket_type_id", "")
+    start_at = tg.entry_start_at if hasattr(tg, "entry_start_at") else tg.get("entry_start_at")
+    end_at = tg.entry_end_at if hasattr(tg, "entry_end_at") else tg.get("entry_end_at")
+
+    date_str = start_at.strftime("%-d %b %Y, %H:%M") if start_at else ""
+    if end_at:
+        date_str += f" \u2013 {end_at.strftime('%-d %b %Y, %H:%M')}"
+
+    return {
+        "entry_name": name,
+        "ticket_type_name": tt_name or None,
+        "price": float(price or 0),
+        "quantity": quantity,
+        "line_total": float(line_total or 0),
+        "entry_id": entry_id,
+        "ticket_type_id": tt_id or None,
+        "date_str": date_str,
+    }
+
+
+def _serialize_page_group(grp: Any) -> dict | None:
+    post = grp.get("post") if isinstance(grp, dict) else getattr(grp, "post", None)
+    cart_items = grp.get("cart_items", []) if isinstance(grp, dict) else getattr(grp, "cart_items", [])
+    cal_entries = grp.get("calendar_entries", []) if isinstance(grp, dict) else getattr(grp, "calendar_entries", [])
+    tickets = grp.get("tickets", []) if isinstance(grp, dict) else getattr(grp, "tickets", [])
+
+    if not cart_items and not cal_entries and not tickets:
+        return None
+
+    post_data = None
+    if post:
+        post_data = {
+            "slug": post.slug if hasattr(post, "slug") else post.get("slug", ""),
+            "title": post.title if hasattr(post, "title") else post.get("title", ""),
+            "feature_image": post.feature_image if hasattr(post, "feature_image") else post.get("feature_image"),
+        }
+    market_place = grp.get("market_place") if isinstance(grp, dict) else getattr(grp, "market_place", None)
+    mp_data = None
+    if market_place:
+        mp_data = {"name": market_place.name if hasattr(market_place, "name") else market_place.get("name", "")}
+
+    return {
+        "post": post_data,
+        "product_count": grp.get("product_count", 0) if isinstance(grp, dict) else getattr(grp, "product_count", 0),
+        "calendar_count": grp.get("calendar_count", 0) if isinstance(grp, dict) else getattr(grp, "calendar_count", 0),
+        "ticket_count": grp.get("ticket_count", 0) if isinstance(grp, dict) else getattr(grp, "ticket_count", 0),
+        "total": float(grp.get("total", 0) if isinstance(grp, dict) else getattr(grp, "total", 0)),
+        "market_place": mp_data,
+    }
+
+
+class CartPageService:
+    """Service for cart page data, callable via (service "cart-page" ...)."""
+
+    async def overview_data(self, session, **kw):
+        from shared.infrastructure.urls import cart_url
+        from bp.cart.services import get_cart_grouped_by_page
+
+        page_groups = await get_cart_grouped_by_page(session)
+        grp_dicts = [d for d in (_serialize_page_group(grp) for grp in page_groups) if d]
+        return {
+            "page_groups": grp_dicts,
+            "cart_url_base": cart_url(""),
+        }
+
+    async def page_cart_data(self, session, **kw):
+        from quart import g, request, url_for
+        from shared.infrastructure.urls import login_url
+        from shared.utils import route_prefix
+        from bp.cart.services import total, calendar_total, ticket_total
+        from bp.cart.services.page_cart import (
+            get_cart_for_page, get_calendar_entries_for_page, get_tickets_for_page,
+        )
+        from bp.cart.services.ticket_groups import group_tickets
+
+        post = g.page_post
+        cart = await get_cart_for_page(session, post.id)
+        cal_entries = await get_calendar_entries_for_page(session, post.id)
+        page_tickets = await get_tickets_for_page(session, post.id)
+        ticket_groups = group_tickets(page_tickets)
+
+        # Build summary data
+        product_qty = sum(ci.quantity for ci in cart) if cart else 0
+        ticket_qty = len(page_tickets) if page_tickets else 0
+        item_count = product_qty + ticket_qty
+
+        product_total = total(cart) or 0
+        cal_total = calendar_total(cal_entries) or 0
+        tk_total = ticket_total(page_tickets) or 0
+        grand = float(product_total) + float(cal_total) + float(tk_total)
+
+        symbol = "\u00a3"
+        if cart and hasattr(cart[0], "product") and getattr(cart[0].product, "regular_price_currency", None):
+            cur = cart[0].product.regular_price_currency
+            symbol = "\u00a3" if cur == "GBP" else cur
+
+        user = getattr(g, "user", None)
+        page_post = getattr(g, "page_post", None)
+
+        summary = {
+            "item_count": item_count,
+            "grand_total": grand,
+            "symbol": symbol,
+            "is_logged_in": bool(user),
+        }
+
+        if user:
+            if page_post:
+                action = url_for("page_cart.page_checkout")
+            else:
+                action = url_for("cart_global.checkout")
+            summary["checkout_action"] = route_prefix() + action
+            summary["user_email"] = user.email
+        else:
+            summary["login_href"] = login_url(request.url)
+
+        return {
+            "cart_items": [_serialize_cart_item(i) for i in cart],
+            "cal_entries": [_serialize_cal_entry(e) for e in cal_entries],
+            "ticket_groups": [_serialize_ticket_group(tg) for tg in ticket_groups],
+            "summary": summary,
+        }
+
+    async def payments_data(self, session, **kw):
+        from shared.sx.page import get_template_context
+
+        ctx = await get_template_context()
+        page_config = ctx.get("page_config")
+        pc_data = None
+        if page_config:
+            pc_data = {
+                "sumup_api_key": bool(getattr(page_config, "sumup_api_key", None)),
+                "sumup_merchant_code": getattr(page_config, "sumup_merchant_code", None) or "",
+                "sumup_checkout_prefix": getattr(page_config, "sumup_checkout_prefix", None) or "",
+            }
+        return {"page_config": pc_data}