feat: enhance message encryption and media file conversion with improved compression and base64 encoding

app/src/main/java/com/rosetta/messenger/utils/MediaUtils.kt

@@ -165,15 +165,16 @@ object MediaUtils {
      */
     suspend fun uriToBase64File(context: Context, uri: Uri): String? = withContext(Dispatchers.IO) {
         try {
-            
-            val inputStream = context.contentResolver.openInputStream(uri) 
+
+            val inputStream = context.contentResolver.openInputStream(uri)
                 ?: return@withContext null
-            
+
             val bytes = inputStream.readBytes()
             inputStream.close()
-            
-            val base64 = Base64.encodeToString(bytes, Base64.NO_WRAP)
-            
+
+            val mimeType = context.contentResolver.getType(uri) ?: "application/octet-stream"
+            val base64 = "data:$mimeType;base64," + Base64.encodeToString(bytes, Base64.NO_WRAP)
+
             base64
         } catch (e: Exception) {
             null