Remove try/except around page registry build

This was silently masking the str.format() braces bug. If page
registry building fails, it should crash visibly, not serve a
broken page with 0 routes.

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

shared/sx/helpers.py

@@ -754,13 +754,8 @@ def sx_page(ctx: dict, page_sx: str, *,
         styles_json = _build_style_dict_json()
 
     # Page registry for client-side routing
-    pages_sx = ""
-    try:
-        from quart import current_app
-        pages_sx = _build_pages_sx(current_app.name)
-    except Exception as e:
-        import logging
-        logging.getLogger("sx").warning("Failed to build page registry: %s", e)
+    from quart import current_app
+    pages_sx = _build_pages_sx(current_app.name)
 
     return _SX_PAGE_TEMPLATE.format(
         title=_html_escape(title),