refactor(frontend): unify list and create pages with compact topbar layout

Move resource list and guide page titles into the shared topbar, introduce ListPageLayout for tighter spacing, and align knowledge edit with the prompt editor chrome.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/ui/list-toolbar.tsx

@@ -15,7 +15,7 @@ export function ListToolbar({ filters, search, className }: ListToolbarProps) {
   return (
     <div
       className={cn(
-        "mb-6 flex flex-col gap-4 lg:flex-row lg:items-center lg:justify-between",
+        "mb-4 flex flex-col gap-3 lg:flex-row lg:items-center lg:justify-between",
         className,
       )}
     >