feat: Add loading of blur preview for images in ZoomableImage component

app/src/main/java/com/rosetta/messenger/ui/chats/components/ImageViewerScreen.kt

@@ -300,6 +300,7 @@ private fun ZoomableImage(
     val scope = rememberCoroutineScope()
     
     var bitmap by remember { mutableStateOf<Bitmap?>(null) }
+    var previewBitmap by remember { mutableStateOf<Bitmap?>(null) }
     var isLoading by remember { mutableStateOf(true) }
     var loadError by remember { mutableStateOf<String?>(null) }
     
@@ -331,6 +332,21 @@ private fun ZoomableImage(
     val minScale = 1f
     val maxScale = 5f
     
+    // Load preview first
+    LaunchedEffect(image.preview) {
+        withContext(Dispatchers.IO) {
+            try {
+                // Декодируем blur preview (после ::)
+                if (image.preview.contains("::")) {
+                    val blurPart = image.preview.substringAfter("::")
+                    previewBitmap = base64ToBitmapSafe(blurPart)
+                }
+            } catch (e: Exception) {
+                Log.e(TAG, "Failed to load preview: ${e.message}")
+            }
+        }
+    }
+    
     // Load image
     LaunchedEffect(image.attachmentId) {
         isLoading = true
@@ -514,6 +530,16 @@ private fun ZoomableImage(
             },
         contentAlignment = Alignment.Center
     ) {
+        // Blur preview в фоне
+        if (previewBitmap != null && bitmap == null) {
+            Image(
+                bitmap = previewBitmap!!.asImageBitmap(),
+                contentDescription = "Preview",
+                modifier = Modifier.fillMaxSize(),
+                contentScale = ContentScale.Fit
+            )
+        }
+        
         when {
             isLoading -> {
                 CircularProgressIndicator(