Slim sxc/pages/__init__.py for federation, test, cart, blog

Move render functions, layouts, helpers, and utils from __init__.py
to sub-modules (renders.py, layouts.py, helpers.py, utils.py).
Update all bp route imports to point at sub-modules directly.
Each __init__.py is now ≤20 lines of setup + registration.

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

cart/sxc/pages/utils.py

@@ -0,0 +1,40 @@
+"""Cart page utilities — serializers and formatters."""
+from __future__ import annotations
+
+from typing import Any
+
+
+def _serialize_order(order: Any) -> dict:
+    from shared.infrastructure.urls import market_product_url
+    created = order.created_at.strftime("%-d %b %Y, %H:%M") if order.created_at else "\u2014"
+    items = []
+    if order.items:
+        for item in order.items:
+            items.append({
+                "product_image": item.product_image,
+                "product_title": item.product_title or "Unknown product",
+                "product_id": item.product_id,
+                "product_slug": item.product_slug,
+                "product_url": market_product_url(item.product_slug),
+                "quantity": item.quantity,
+                "unit_price_formatted": f"{item.unit_price or 0:.2f}",
+                "currency": item.currency or order.currency or "GBP",
+            })
+    return {
+        "id": order.id,
+        "status": order.status or "pending",
+        "created_at_formatted": created,
+        "description": order.description or "",
+        "total_formatted": f"{order.total_amount or 0:.2f}",
+        "total_amount": float(order.total_amount or 0),
+        "currency": order.currency or "GBP",
+        "items": items,
+    }
+
+
+def _serialize_calendar_entry(e: Any) -> dict:
+    st = e.state or ""
+    ds = e.start_at.strftime("%-d %b %Y, %H:%M") if e.start_at else ""
+    if e.end_at:
+        ds += f" \u2013 {e.end_at.strftime('%-d %b %Y, %H:%M')}"
+    return {"name": e.name, "state": st, "date_str": ds, "cost_formatted": f"{e.cost or 0:.2f}"}