parsed based64 encoded daily sinexcel data

csharp/App/Backend/Services/AggregatedJsonParser.cs

@@ -1,3 +1,4 @@
+using System.Text;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using InnovEnergy.App.Backend.DataTypes;
@@ -115,6 +116,7 @@ public static class AggregatedJsonParser
     /// Tries to read an aggregated JSON file from the installation's S3 bucket.
     /// S3 key: DDMMYYYY.json (directly in bucket root).
     /// Returns file content or null if not found / error.
+    /// Handles base64-encoded files (SinexcelCommunication uploads base64).
     /// </summary>
     public static async Task<String?> TryReadFromS3(Installation installation, String isoDate)
     {
@@ -125,7 +127,8 @@ public static class AggregatedJsonParser
             var bucket   = region.Bucket(installation.BucketName());
             var s3Url    = bucket.Path(fileName);
 
-            return await s3Url.GetObjectAsString();
+            var raw = await s3Url.GetObjectAsString();
+            return DecodeContent(raw);
         }
         catch (Exception ex)
         {
@@ -134,6 +137,29 @@ public static class AggregatedJsonParser
         }
     }
 
+    /// <summary>
+    /// Decodes S3 file content. SinexcelCommunication devices upload DDMMYYYY.json
+    /// as base64-encoded NDJSON. If the content doesn't start with '{' it is
+    /// assumed to be base64 and decoded accordingly.
+    /// </summary>
+    private static String DecodeContent(String raw)
+    {
+        var trimmed = raw.Trim();
+        if (trimmed.StartsWith('{'))
+            return raw;
+
+        try
+        {
+            var decoded = Encoding.UTF8.GetString(Convert.FromBase64String(trimmed));
+            Console.WriteLine("[AggregatedJsonParser] Decoded base64-encoded S3 content");
+            return decoded;
+        }
+        catch
+        {
+            return raw;
+        }
+    }
+
     // --- JSON DTOs ---
 
     private sealed class HourlyJsonDto