Rebrand sexp → sx across web platform (173 files)

Rename all sexp directories, files, identifiers, and references to sx.
artdag/ excluded (separate media processing DSL).

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

market/bp/fragments/routes.py

@@ -1,6 +1,6 @@
 """Market app fragment endpoints.
 
-Exposes sexp fragments at ``/internal/fragments/<type>`` for consumption
+Exposes sx fragments at ``/internal/fragments/<type>`` for consumption
 by other coop apps via the fragment client.
 """
 
@@ -26,16 +26,16 @@ def register():
     async def get_fragment(fragment_type: str):
         handler = _handlers.get(fragment_type)
         if handler is None:
-            return Response("", status=200, content_type="text/sexp")
+            return Response("", status=200, content_type="text/sx")
         src = await handler()
-        return Response(src, status=200, content_type="text/sexp")
+        return Response(src, status=200, content_type="text/sx")
 
     # --- container-nav fragment: market links --------------------------------
 
     async def _container_nav_handler():
         from quart import current_app
         from shared.infrastructure.urls import market_url
-        from shared.sexp.helpers import sexp_call
+        from shared.sx.helpers import sx_call
 
         container_type = request.args.get("container_type", "page")
         container_id = int(request.args.get("container_id", 0))
@@ -51,7 +51,7 @@ def register():
         parts = []
         for m in markets:
             href = market_url(f"/{post_slug}/{m.slug}/")
-            parts.append(sexp_call("market-link-nav",
+            parts.append(sx_call("market-link-nav",
                                    href=href, name=m.name, nav_class=nav_class))
         return "(<> " + " ".join(parts) + ")"
 
@@ -59,15 +59,15 @@ def register():
 
     # --- link-card fragment: product preview card --------------------------------
 
-    def _product_link_card_sexp(product, link: str) -> str:
-        from shared.sexp.helpers import sexp_call
+    def _product_link_card_sx(product, link: str) -> str:
+        from shared.sx.helpers import sx_call
         subtitle = product.brand or ""
         detail = ""
         if product.special_price:
             detail = f"{product.regular_price} → {product.special_price}"
         elif product.regular_price:
             detail = str(product.regular_price)
-        return sexp_call("link-card",
+        return sx_call("link-card",
                          title=product.title, image=product.image,
                          subtitle=subtitle, detail=detail,
                          link=link)
@@ -90,7 +90,7 @@ def register():
                     await g.s.execute(select(Product).where(Product.slug == s))
                 ).scalar_one_or_none()
                 if product:
-                    parts.append(_product_link_card_sexp(
+                    parts.append(_product_link_card_sx(
                         product, market_url(f"/product/{product.slug}/")))
             return "\n".join(parts)
 
@@ -102,7 +102,7 @@ def register():
         ).scalar_one_or_none()
         if not product:
             return ""
-        return _product_link_card_sexp(product, market_url(f"/product/{product.slug}/"))
+        return _product_link_card_sx(product, market_url(f"/product/{product.slug}/"))
 
     _handlers["link-card"] = _link_card_handler