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>

blog/bp/post/admin/routes.py

@@ -11,7 +11,7 @@ from quart import (
 )
 from shared.browser.app.authz import require_admin, require_post_author
 from markupsafe import escape
-from shared.sx.helpers import sx_response, render_to_sx
+from shared.sx.helpers import sx_response, sx_call
 from shared.sx.parser import SxExpr, serialize as sx_serialize
 from shared.utils import host_url
 
@@ -60,10 +60,10 @@ def _post_to_edit_dict(post) -> dict:
     return d
 
 
-async def _render_features(features, post, result):
+def _render_features(features, post, result):
     """Render features panel via .sx defcomp."""
     slug = post.get("slug", "")
-    return await render_to_sx("blog-features-panel-content",
+    return sx_call("blog-features-panel-content",
         features_url=host_url(url_for("blog.post.admin.update_features", slug=slug)),
         calendar_checked=bool(features.get("calendar")),
         market_checked=bool(features.get("market")),
@@ -187,7 +187,7 @@ def _render_calendar_view(
     return _raw_html_sx(html)
 
 
-async def _render_associated_entries(all_calendars, associated_entry_ids, post_slug: str) -> str:
+def _render_associated_entries(all_calendars, associated_entry_ids, post_slug: str) -> str:
     """Render the associated entries panel."""
     from shared.browser.app.csrf import generate_csrf_token
     from quart import url_for as qurl
@@ -216,13 +216,13 @@ async def _render_associated_entries(all_calendars, associated_entry_ids, post_s
 
             toggle_url = host_url(qurl("blog.post.admin.toggle_entry", slug=post_slug, entry_id=e_id))
 
-            img_sx = await render_to_sx("blog-entry-image", src=cal_fi, title=cal_title)
+            img_sx = sx_call("blog-entry-image", src=cal_fi, title=cal_title)
 
             date_str = e_start.strftime("%A, %B %d, %Y at %H:%M") if e_start else ""
             if e_end:
                 date_str += f" \u2013 {e_end.strftime('%H:%M')}"
 
-            entry_items.append(await render_to_sx("blog-associated-entry",
+            entry_items.append(sx_call("blog-associated-entry",
                 confirm_text=f"This will remove {e_name} from this post",
                 toggle_url=toggle_url,
                 hx_headers=f'{{"X-CSRFToken": "{csrf}"}}',
@@ -231,16 +231,16 @@ async def _render_associated_entries(all_calendars, associated_entry_ids, post_s
             ))
 
     if has_entries:
-        content_sx = await render_to_sx("blog-associated-entries-content",
+        content_sx = sx_call("blog-associated-entries-content",
             items=SxExpr("(<> " + " ".join(entry_items) + ")"),
         )
     else:
-        content_sx = await render_to_sx("blog-associated-entries-empty")
+        content_sx = sx_call("blog-associated-entries-empty")
 
-    return await render_to_sx("blog-associated-entries-panel", content=SxExpr(content_sx))
+    return sx_call("blog-associated-entries-panel", content=SxExpr(content_sx))
 
 
-async def _render_nav_entries_oob(associated_entries, calendars, post: dict) -> str:
+def _render_nav_entries_oob(associated_entries, calendars, post: dict) -> str:
     """Render the OOB nav entries swap."""
     entries_list = []
     if associated_entries and hasattr(associated_entries, "entries"):
@@ -249,7 +249,7 @@ async def _render_nav_entries_oob(associated_entries, calendars, post: dict) ->
     has_items = bool(entries_list or calendars)
 
     if not has_items:
-        return await render_to_sx("blog-nav-entries-empty")
+        return sx_call("blog-nav-entries-empty")
 
     select_colours = (
         "[.hover-capable_&]:hover:bg-yellow-300"
@@ -291,7 +291,7 @@ async def _render_nav_entries_oob(associated_entries, calendars, post: dict) ->
             entry_path = f"/{post_slug}/{cal_slug}/"
             date_str = ""
 
-        item_parts.append(await render_to_sx("calendar-entry-nav",
+        item_parts.append(sx_call("calendar-entry-nav",
             href=entry_path, nav_class=nav_cls, name=e_name, date_str=date_str,
         ))
 
@@ -300,13 +300,13 @@ async def _render_nav_entries_oob(associated_entries, calendars, post: dict) ->
         cal_slug = getattr(calendar, "slug", "")
         cal_path = f"/{post_slug}/{cal_slug}/"
 
-        item_parts.append(await render_to_sx("blog-nav-calendar-item",
+        item_parts.append(sx_call("blog-nav-calendar-item",
             href=cal_path, nav_cls=nav_cls, name=cal_name,
         ))
 
     items_sx = "(<> " + " ".join(item_parts) + ")" if item_parts else ""
 
-    return await render_to_sx("scroll-nav-wrapper",
+    return sx_call("scroll-nav-wrapper",
         wrapper_id="entries-calendars-nav-wrapper", container_id="associated-items-container",
         arrow_cls="entries-nav-arrow",
         left_hs="on click set #associated-items-container.scrollLeft to #associated-items-container.scrollLeft - 200",
@@ -353,7 +353,7 @@ def register():
     })
 
     features = result.get("features", {})
-    html = await _render_features(features, post, result)
+    html = _render_features(features, post, result)
     return sx_response(html)
 
   @bp.put("/admin/sumup/")
@@ -386,7 +386,7 @@ def register():
     result = await call_action("blog", "update-page-config", payload=payload)
 
     features = result.get("features", {})
-    html = await _render_features(features, post, result)
+    html = _render_features(features, post, result)
     return sx_response(html)
 
   @bp.get("/entries/calendar/<int:calendar_id>/")
@@ -508,8 +508,8 @@ def register():
 
     # Return the associated entries admin list + OOB update for nav entries
     post = g.post_data["post"]
-    admin_list = await _render_associated_entries(all_calendars, associated_entry_ids, post["slug"])
-    nav_entries_html = await _render_nav_entries_oob(associated_entries, calendars, post)
+    admin_list = _render_associated_entries(all_calendars, associated_entry_ids, post["slug"])
+    nav_entries_html = _render_nav_entries_oob(associated_entries, calendars, post)
 
     return sx_response(admin_list + nav_entries_html)
 
@@ -686,7 +686,7 @@ def register():
 
     slug = post.get("slug", "")
     create_url = host_url(url_for("blog.post.admin.create_market", slug=slug))
-    html = await render_to_sx("blog-markets-panel-content",
+    html = sx_call("blog-markets-panel-content",
         markets=_serialize_markets(page_markets, slug), create_url=create_url)
     return sx_response(html)
 
@@ -715,7 +715,7 @@ def register():
 
     slug = post.get("slug", "")
     create_url = host_url(url_for("blog.post.admin.create_market", slug=slug))
-    html = await render_to_sx("blog-markets-panel-content",
+    html = sx_call("blog-markets-panel-content",
         markets=_serialize_markets(page_markets, slug), create_url=create_url)
     return sx_response(html)
 
@@ -738,7 +738,7 @@ def register():
 
     slug = post.get("slug", "")
     create_url = host_url(url_for("blog.post.admin.create_market", slug=slug))
-    html = await render_to_sx("blog-markets-panel-content",
+    html = sx_call("blog-markets-panel-content",
         markets=_serialize_markets(page_markets, slug), create_url=create_url)
     return sx_response(html)