update chat screen

shared/src/commonMain/kotlin/su/reya/coop/NostrViewModel.kt

@@ -80,7 +80,7 @@ class NostrViewModel(
                     }
 
                     val now = Clock.System.now().toEpochMilliseconds()
-                    if (batch.size >= 20 || (now - lastFlushTime) >= timeout || nextKey == null) {
+                    if (batch.size >= 10 || (now - lastFlushTime) >= timeout || nextKey == null) {
                         val keysToRequest = batch.toList()
                         batch.clear()
                         nostr.fetchMetadataBatch(keysToRequest)
@@ -271,6 +271,11 @@ class NostrViewModel(
         }
     }
 
+    fun getChatRoom(id: Long): Room {
+        return chatRooms.value.firstOrNull { it.id == id }
+            ?: throw IllegalArgumentException("Room not found")
+    }
+
     fun getChatRooms() {
         viewModelScope.launch {
             try {