fixed chat textjson format, selected session for all, fixed android echo

android/src/screens/ChatScreen.tsx

@@ -96,14 +96,23 @@ const ChatScreen: React.FC = () => {
         const sender = (message.payload.sender as string) || '';
         if (sender === 'user' || sender === 'diagnostic') return;
 
-        const ariaMsg: ChatMessage = {
-          id: nextId(),
-          sender: 'aria',
-          text: (message.payload.text as string) || '',
-          timestamp: message.timestamp,
-          attachments: message.payload.attachments as Attachment[] | undefined,
-        };
-        setMessages(prev => [...prev, ariaMsg]);
+        const text = (message.payload.text as string) || '';
+        const ts = message.timestamp;
+        // Duplikat-Schutz: gleicher Text innerhalb 5s ignorieren
+        setMessages(prev => {
+          const isDuplicate = prev.some(m =>
+            m.sender === 'aria' && m.text === text && Math.abs(m.timestamp - ts) < 5000
+          );
+          if (isDuplicate) return prev;
+          const ariaMsg: ChatMessage = {
+            id: nextId(),
+            sender: 'aria',
+            text,
+            timestamp: ts,
+            attachments: message.payload.attachments as Attachment[] | undefined,
+          };
+          return [...prev, ariaMsg];
+        });
       }
 
       // TTS-Audio abspielen wenn vorhanden