Remove render_to_sx from public API: enforce sx_call for all service code

Replace ~250 render_to_sx calls across all services with sync sx_call,
converting many async functions to sync where no other awaits remained.
Make render_to_sx/render_to_sx_with_env private (_render_to_sx).
Add (post-header-ctx) IO primitive and shared post/post-admin defmacros.
Convert built-in post/post-admin layouts from Python to register_sx_layout
with .sx defcomps. Remove dead post_admin_mobile_nav_sx.

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

market/sxc/pages/cards.py

@@ -4,7 +4,7 @@ from __future__ import annotations
 from typing import Any
 
 from shared.sx.parser import SxExpr
-from shared.sx.helpers import render_to_sx
+from shared.sx.helpers import sx_call
 
 from .utils import _set_prices, _price_str
 from .filters import _MOBILE_SENTINEL_HS, _DESKTOP_SENTINEL_HS
@@ -14,7 +14,7 @@ from .filters import _MOBILE_SENTINEL_HS, _DESKTOP_SENTINEL_HS
 # Product card (browse grid item)
 # ---------------------------------------------------------------------------
 
-async def _product_card_sx(p: dict, ctx: dict) -> str:
+def _product_card_sx(p: dict, ctx: dict) -> str:
     """Build a single product card for browse grid as sx call."""
     from quart import url_for
     from shared.browser.app.csrf import generate_csrf_token
@@ -98,10 +98,10 @@ async def _product_card_sx(p: dict, ctx: dict) -> str:
         kwargs["search_mid"] = search_mid
         kwargs["search_post"] = search_post
 
-    return await render_to_sx("market-product-card", **kwargs)
+    return sx_call("market-product-card", **kwargs)
 
 
-async def _product_cards_sx(ctx: dict) -> str:
+def _product_cards_sx(ctx: dict) -> str:
     """S-expression wire format for product cards (client renders)."""
     from shared.utils import route_prefix
 
@@ -114,7 +114,7 @@ async def _product_cards_sx(ctx: dict) -> str:
 
     parts = []
     for p in products:
-        parts.append(await _product_card_sx(p, ctx))
+        parts.append(_product_card_sx(p, ctx))
 
     if page < total_pages:
         if callable(qs_fn):
@@ -122,25 +122,25 @@ async def _product_cards_sx(ctx: dict) -> str:
         else:
             next_qs = f"?page={page + 1}"
         next_url = prefix + current_local_href + next_qs
-        parts.append(await render_to_sx("sentinel-mobile",
+        parts.append(sx_call("sentinel-mobile",
                                id=f"sentinel-{page}-m", next_url=next_url,
                                hyperscript=_MOBILE_SENTINEL_HS))
-        parts.append(await render_to_sx("sentinel-desktop",
+        parts.append(sx_call("sentinel-desktop",
                                id=f"sentinel-{page}-d", next_url=next_url,
                                hyperscript=_DESKTOP_SENTINEL_HS))
     else:
-        parts.append(await render_to_sx("end-of-results"))
+        parts.append(sx_call("end-of-results"))
 
     return "(<> " + " ".join(parts) + ")"
 
 
-async def _like_button_sx(slug: str, liked: bool, csrf: str, ctx: dict) -> str:
+def _like_button_sx(slug: str, liked: bool, csrf: str, ctx: dict) -> str:
     """Build the like/unlike heart button overlay as sx."""
     from quart import url_for
 
     action = url_for("market.browse.product.like_toggle", product_slug=slug)
     icon_cls = "fa-solid fa-heart text-red-500" if liked else "fa-regular fa-heart text-stone-400"
-    return await render_to_sx(
+    return sx_call(
         "market-like-button",
         form_id=f"like-{slug}", action=action, slug=slug,
         csrf=csrf, icon_cls=icon_cls,
@@ -151,7 +151,7 @@ async def _like_button_sx(slug: str, liked: bool, csrf: str, ctx: dict) -> str:
 # Market cards (all markets / page markets)
 # ---------------------------------------------------------------------------
 
-async def _market_card_sx(market: Any, page_info: dict, *, show_page_badge: bool = True,
+def _market_card_sx(market: Any, page_info: dict, *, show_page_badge: bool = True,
                       post_slug: str = "") -> str:
     """Build a single market card as sx."""
     from shared.infrastructure.urls import market_url
@@ -173,20 +173,20 @@ async def _market_card_sx(market: Any, page_info: dict, *, show_page_badge: bool
 
     title_sx = ""
     if market_href:
-        title_sx = await render_to_sx("market-market-card-title-link", href=market_href, name=name)
+        title_sx = sx_call("market-market-card-title-link", href=market_href, name=name)
     else:
-        title_sx = await render_to_sx("market-market-card-title", name=name)
+        title_sx = sx_call("market-market-card-title", name=name)
 
     desc_sx = ""
     if description:
-        desc_sx = await render_to_sx("market-market-card-desc", description=description)
+        desc_sx = sx_call("market-market-card-desc", description=description)
 
     badge_sx = ""
     if show_page_badge and p_title:
         badge_href = market_url(f"/{p_slug}/")
-        badge_sx = await render_to_sx("market-market-card-badge", href=badge_href, title=p_title)
+        badge_sx = sx_call("market-market-card-badge", href=badge_href, title=p_title)
 
-    return await render_to_sx(
+    return sx_call(
         "market-market-card",
         title_content=SxExpr(title_sx) if title_sx else None,
         desc_content=SxExpr(desc_sx) if desc_sx else None,
@@ -194,30 +194,30 @@ async def _market_card_sx(market: Any, page_info: dict, *, show_page_badge: bool
     )
 
 
-async def _market_cards_sx(markets: list, page_info: dict, page: int, has_more: bool,
+def _market_cards_sx(markets: list, page_info: dict, page: int, has_more: bool,
                         next_url: str, *, show_page_badge: bool = True,
                         post_slug: str = "") -> str:
     """Build market cards with infinite scroll sentinel as sx."""
     parts = []
     for m in markets:
-        parts.append(await _market_card_sx(m, page_info, show_page_badge=show_page_badge,
+        parts.append(_market_card_sx(m, page_info, show_page_badge=show_page_badge,
                                 post_slug=post_slug))
     if has_more:
-        parts.append(await render_to_sx(
+        parts.append(sx_call(
             "sentinel-simple",
             id=f"sentinel-{page}", next_url=next_url,
         ))
     return "(<> " + " ".join(parts) + ")"
 
 
-async def _markets_grid(cards_sx: str) -> str:
+def _markets_grid(cards_sx: str) -> str:
     """Wrap market cards in a grid as sx."""
-    return await render_to_sx("market-markets-grid", cards=SxExpr(cards_sx))
+    return sx_call("market-markets-grid", cards=SxExpr(cards_sx))
 
 
-async def _no_markets_sx(message: str = "No markets available") -> str:
+def _no_markets_sx(message: str = "No markets available") -> str:
     """Empty state for markets as sx."""
-    return await render_to_sx("empty-state", icon="fa fa-store", message=message,
+    return sx_call("empty-state", icon="fa fa-store", message=message,
                     cls="px-3 py-12 text-center text-stone-400")
 
 
@@ -225,14 +225,14 @@ async def _no_markets_sx(message: str = "No markets available") -> str:
 # Market landing page
 # ---------------------------------------------------------------------------
 
-async def _market_landing_content_sx(post: dict) -> str:
+def _market_landing_content_sx(post: dict) -> str:
     """Build market landing page content as sx."""
     parts: list[str] = []
     if post.get("custom_excerpt"):
-        parts.append(await render_to_sx("market-landing-excerpt", text=post["custom_excerpt"]))
+        parts.append(sx_call("market-landing-excerpt", text=post["custom_excerpt"]))
     if post.get("feature_image"):
-        parts.append(await render_to_sx("market-landing-image", src=post["feature_image"]))
+        parts.append(sx_call("market-landing-image", src=post["feature_image"]))
     if post.get("html"):
-        parts.append(await render_to_sx("market-landing-html", html=post["html"]))
+        parts.append(sx_call("market-landing-html", html=post["html"]))
     inner = "(<> " + " ".join(parts) + ")" if parts else "(<>)"
-    return await render_to_sx("market-landing-content", inner=SxExpr(inner))
+    return sx_call("market-landing-content", inner=SxExpr(inner))