fix(ui): mobile modal scroll behavior (#412)

* docs: add announcement popup design spec

* docs: add announcement popup implementation plan

* fix(ui): change modal scroll behavior to inside for mobile screens

Fixes layout issue where modal footer and action buttons are pushed off screen on mobile devices.

vite-frontend/src/layouts/admin.tsx

@@ -662,7 +662,7 @@ export default function AdminLayout({
         }}
         isOpen={isOpen}
         placement="center"
-        scrollBehavior="outside"
+        scrollBehavior="inside"
         size="2xl"
         onOpenChange={() => {
           onOpenChange();