feat: enhance avatar handling and file attachment functionality with improved UI interactions

app/src/main/java/com/rosetta/messenger/data/MessageRepository.kt

@@ -139,9 +139,15 @@ class MessageRepository private constructor(private val context: Context) {
     /** Инициализация с текущим аккаунтом */
     fun initialize(publicKey: String, privateKey: String) {
         val start = System.currentTimeMillis()
-        // 🔥 Очищаем кэш запрошенных user info при смене аккаунта
+        // 🔥 Очищаем кэши при смене аккаунта
         if (currentAccount != publicKey) {
             requestedUserInfoKeys.clear()
+            // Clear message Flow cache — dialogKey is account-independent (sorted pair),
+            // so stale Flows from previous account would return wrong data
+            messageCache.clear()
+            // Clear processed messageIds — prevents blocking delivery of messages
+            // that were already processed under the previous account
+            clearProcessedCache()
         }
 
         currentAccount = publicKey