fix: random crash due to no messages availables in signal

src/app/signals/messages.nim

@@ -4,29 +4,30 @@ import types
 proc fromEvent*(event: JsonNode): Signal = 
   var signal:ChatSignal = ChatSignal()
   signal.messages = @[]
-  for jsonMsg in event["event"]["messages"]:
-    let msg = Message(
-      alias: jsonMsg["alias"].getStr,
-      chatId: jsonMsg["chatId"].getStr,
-      clock: $jsonMsg["clock"].getInt,
-      contentType: jsonMsg["contentType"].getInt,
-      ensName: jsonMsg["ensName"].getStr,
-      fromAuthor: jsonMsg["from"].getStr,
-      id: jsonMsg["identicon"].getStr,
-      identicon: jsonMsg["identicon"].getStr,
-      lineCount: jsonMsg["lineCount"].getInt,
-      localChatId: jsonMsg["localChatId"].getStr,
-      messageType: jsonMsg["messageType"].getStr,
-      replace: jsonMsg["replace"].getStr,
-      responseTo: jsonMsg["responseTo"].getStr,
-      rtl: jsonMsg["rtl"].getBool,
-      seen: jsonMsg["seen"].getBool,
-      text: jsonMsg["text"].getStr,
-      timestamp: $jsonMsg["timestamp"].getInt,
-      whisperTimestamp: $jsonMsg["whisperTimestamp"].getInt,
-      isCurrentUser: false # TODO: this must compare the fromAuthor against current user because the messages received from the mailserver will arrive as signals too, and those include the current user messages
-    )
 
-    signal.messages.add(msg)
+  if event["event"]{"messages"} != nil:
+    for jsonMsg in event["event"]["messages"]:
+      let msg = Message(
+        alias: jsonMsg{"alias"}.getStr,
+        chatId: jsonMsg{"chatId"}.getStr,
+        clock: $jsonMsg{"clock"}.getInt,
+        contentType: jsonMsg{"contentType"}.getInt,
+        ensName: jsonMsg{"ensName"}.getStr,
+        fromAuthor: jsonMsg{"from"}.getStr,
+        id: jsonMsg{"identicon"}.getStr,
+        identicon: jsonMsg{"identicon"}.getStr,
+        lineCount: jsonMsg{"lineCount"}.getInt,
+        localChatId: jsonMsg{"localChatId"}.getStr,
+        messageType: jsonMsg{"messageType"}.getStr,
+        replace: jsonMsg{"replace"}.getStr,
+        responseTo: jsonMsg{"responseTo"}.getStr,
+        rtl: jsonMsg{"rtl"}.getBool,
+        seen: jsonMsg{"seen"}.getBool,
+        text: jsonMsg{"text"}.getStr,
+        timestamp: $jsonMsg{"timestamp"}.getInt,
+        whisperTimestamp: $jsonMsg{"whisperTimestamp"}.getInt,
+        isCurrentUser: false # TODO: this must compare the fromAuthor against current user because the messages received from the mailserver will arrive as signals too, and those include the current user messages
+      )
+      signal.messages.add(msg)
 
   result = signal