Refactor and optimize various components

- Updated RosettaFirebaseMessagingService to use IO dispatcher for blocking calls.
- Enhanced AvatarRepository with LRU caching and improved coroutine handling for avatar loading.
- Implemented timeout for websocket connection in UnlockScreen.
- Added selection mode functionality in ChatsListScreen with haptic feedback and improved UI for chat actions.
- Improved animated dots in AttachmentComponents for a smoother visual effect.
- Refactored image downloading and caching logic in ChatDetailComponents to streamline the process.
- Optimized SwipeBackContainer to simplify gesture handling.
- Adjusted swipe back behavior in OtherProfileScreen based on image viewer state.

app/src/main/java/com/rosetta/messenger/crypto/MessageCrypto.kt

@@ -24,6 +24,10 @@ object MessageCrypto {
     private const val CHACHA_KEY_SIZE = 32
     private const val XCHACHA_NONCE_SIZE = 24
     private const val POLY1305_TAG_SIZE = 16
+
+    // Кэш PBKDF2-SHA256 ключей: password → derived key bytes
+    // PBKDF2 с 1000 итерациями ~50-100ms, кэш убирает повторные вычисления
+    private val pbkdf2Cache = java.util.concurrent.ConcurrentHashMap<String, ByteArray>()
     
     init {
         if (Security.getProvider(BouncyCastleProvider.PROVIDER_NAME) == null) {
@@ -608,6 +612,13 @@ object MessageCrypto {
      * но PBEKeySpec в Java использует UTF-16! Поэтому используем ручную реализацию.
      */
     private fun generatePBKDF2Key(password: String, salt: String = "rosetta", iterations: Int = 1000): ByteArray {
+        // Кэшируем только для дефолтных salt/iterations (99% вызовов)
+        if (salt == "rosetta" && iterations == 1000) {
+            return pbkdf2Cache.getOrPut(password) {
+                val passwordBytes = password.toByteArray(Charsets.UTF_8)
+                generatePBKDF2KeyFromBytes(passwordBytes, salt.toByteArray(Charsets.UTF_8), iterations)
+            }
+        }
         // Crypto-js: WordArray.create(password) использует UTF-8
         val passwordBytes = password.toByteArray(Charsets.UTF_8)
         return generatePBKDF2KeyFromBytes(passwordBytes, salt.toByteArray(Charsets.UTF_8), iterations)