Refactor EnvelopeReceiverExecutor and Repository methods

- Updated `EnvelopeReceiverExecutor` to inherit from `SQLExecutor` and added `_erRepository` for enhanced data access.
- Introduced `AddEnvelopeReceiverAsync` method for retrieving envelope receivers.
- Modified `ReadById` in `EnvelopeReceiverRepository` to support flexible querying with new parameters.
- Updated `ReadByIdAsync` to align with changes in `ReadById`.

EnvelopeGenerator.Infrastructure/Repositories/EnvlopeReceiverRepository.cs

@@ -48,9 +48,19 @@ public class EnvelopeReceiverRepository : CRUDRepository<EnvelopeReceiver, (int
 
     public async Task<int> CountAsync(string uuid, string signature) => await ReadWhere(uuid: uuid, signature: signature).CountAsync();
 
-    private IQueryable<EnvelopeReceiver> ReadById(int envelopeId, int receiverId, bool readOnly = true)
+    private IQueryable<EnvelopeReceiver> ReadById(int envelopeId, int receiverId, bool withEnvelope = true, bool withReceiver = true, bool readOnly = true)
     {
         var query = readOnly ? _dbSet.AsNoTracking() : _dbSet;
+        
+        if (withEnvelope)
+            query = query
+                .Include(er => er.Envelope).ThenInclude(e => e!.Documents!).ThenInclude(d => d.Elements!.Where(e => e.Receiver!.Id == receiverId))
+                .Include(er => er.Envelope).ThenInclude(e => e!.History)
+                .Include(er => er.Envelope).ThenInclude(e => e!.User);
+
+        if (withReceiver)
+            query = query.Include(er => er.Receiver);
+
         return query.Where(er => er.EnvelopeId == envelopeId && er.ReceiverId == receiverId);
     }