Stacky ignores the answer to its own question unless it is named again #200

Summary

When Stacky asks a question in a room, the person's answer gets no reply unless it starts with "Stacky", so a conversation Stacky started dies silently.

Steps to reproduce

1. Demo rig with the agent up; a list partyliste with two open items.
2. In a room with Stacky, as Homer: "Stacky, die Partyliste brauchen wir nicht mehr, lösch sie bitte."
3. Stacky answers in the room: "Die Partyliste hat noch 2 offene Items. Sollen die auch weg?"
4. As Homer, in the room (not in a thread): "Ja, die können weg."

Expected behaviour

Stacky takes the answer to its own question and deletes the list. Stacky now asks before acting on anything unclear (two items that fit, a list with open items), so an answer is the normal next message.

Actual behaviour

No reply, no reaction, nothing in the agent's log: the message is not addressed by name (lib/stack/name_trigger.py) and is not in a thread the agent is part of (stacklets/agent/runtime/thread_trigger.py). "Stacky, ja, die können weg." works.

Environment

feature/rc2 at #199, port mode, agent and memory stacklets.

Definition of done

• The steps above end with the list deleted and a reply, with no name in step 4
• A message from someone else, or one sent long after the question, is still not taken as the answer
• A test states which messages count as the answer to Stacky's question, and which do not