refactor: Improve MyceliumStreamer's message handling

- Removed unnecessary test data from `deduped_mycelium_master.vsh`.
- Simplified `MyceliumStreamer.listen()` to efficiently handle
  incoming messages, removing redundant code and improving readability.
- Enhanced error handling in `MyceliumStreamer.listen()` for more robust
  operation.

examples/data/deduped_mycelium_master.vsh

@@ -19,15 +19,6 @@ println('Starting master node...')
 // Add worker to whitelist and initialize its database
 streamer.add_worker(worker_public_key)!
 
-// Write some test data
-// id := streamer.write(id: 1, value: 'Record 1')!
-// println('Wrote record with ID: ${id}')
-
-// // Verify data in master
-// master_data := streamer.read(id: id)!
-// master_data_str := master_data.bytestr()
-// println('Master data: ${master_data_str}')
-
 // Keep master running to handle worker connections
 mut id_ := u32(1)
 

lib/data/ourdb/mycelium_streamer.v

@@ -126,23 +126,21 @@ pub:
 
 // listen continuously checks for messages from master and applies updates
 pub fn (mut s MyceliumStreamer) listen() ! {
-	println('Listening for updates from master...')
 	spawn fn [mut s] () ! {
-		s.listen_()!
-	}()
-}
-
-fn (mut s MyceliumStreamer) listen_() ! {
-	println('Listening...')
-	msg := s.mycelium_client.receive_msg(wait: true, peek: true, topic: 'db_sync')!
-
-	update_data := base64.decode(msg.payload)
-	if mut worker := s.workers[msg.src_pk] {
-		worker.sync_updates(update_data) or { return error('Failed to sync worker: ${err}') }
+		msg := s.mycelium_client.receive_msg(wait: true, peek: true, topic: 'db_sync') or {
+			return error('Failed to receive message: ${err}')
 		}
-
+		if msg.payload.len > 0 {
+			update_data := base64.decode(msg.payload)
+			if mut worker := s.workers[msg.dst_pk] {
+				worker.sync_updates(update_data) or {
+					return error('Failed to sync worker: ${err}')
+				}
+			}
+		}
+	}()
 	time.sleep(time.second * 1)
-	return s.listen_()
+	return s.listen()
 }
 
 pub fn (mut s MyceliumStreamer) read(args MyceliumReadArgs) ![]u8 {