feat: Improve MyceliumStreamer worker communication

- Add worker registration to MyceliumStreamer:  Allows for explicit
  addition of workers, improving management and control.
- Simplify worker message handling: Streamlines message processing
  for increased efficiency and readability.  Removes unnecessary
  logging and simplifies message routing.
- Remove redundant message handling: Eliminates duplicate code
  paths for cleaner and more maintainable code.
- Improve worker data retrieval: Facilitates direct data retrieval
  from workers, enhancing efficiency and reliability.

examples/data/deduped_mycelium_worker.vsh

@@ -11,5 +11,7 @@ mut streamer := ourdb.new_streamer(
 	is_worker:        true
 )!
 
+streamer.add_worker(worker_public_key)!
+
 // Initialize and run worker node
 streamer.listen()!