Fix examples.sx: paren balance + dict eval crash at startup

1. Extra closing paren in ex-tabs handler
2. tab-content dict values contained (div ...) HTML tags which crash
   during register_components since HTML primitives aren't in env

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

shared/sx/primitives_io.py

@@ -408,6 +408,18 @@ async def _io_request_form_all(
     return dict(form)
 
 
+@register_io_handler("request-form-list")
+async def _io_request_form_list(
+    args: list[Any], kwargs: dict[str, Any], ctx: RequestContext
+) -> list:
+    """``(request-form-list "field")`` → all values for a multi-value form field."""
+    if not args:
+        raise ValueError("request-form-list requires a field name")
+    from quart import request
+    form = await request.form
+    return form.getlist(str(args[0]))
+
+
 @register_io_handler("request-headers-all")
 async def _io_request_headers_all(
     args: list[Any], kwargs: dict[str, Any], ctx: RequestContext