fix(communication): enable scrolling in collaboration management

frontend/pages/communication/collaboration.vue

@@ -80,7 +80,7 @@ onBeforeUnmount(() => clearInterval(timer))
 </script>
 
 <template>
-  <div class="w-full space-y-5 p-4 sm:p-6">
+  <div class="min-h-0 min-w-0 w-full flex-1 space-y-5 overflow-y-auto p-4 sm:p-6">
     <header class="flex flex-wrap items-start justify-between gap-3">
       <div><h1 class="text-2xl font-semibold">Zusammenarbeit</h1><p class="mt-1 text-sm text-gray-500">Gemeinsame Chats und geschützte Projekt-Unterräume</p></div>
       <div class="flex flex-wrap gap-2">