Merge branch 'feat/multiple-receivers' into 'dev'

feat: able to send to multiple receivers

See merge request ics/sp/2025/n25b/pepperplus-cb!42

src/control_backend/core/agent_system.py

@@ -133,6 +133,7 @@ class BaseAgent(ABC):
 
         :param message: The message to send.
         """
+        message.sender = self.name
         to = message.to
         receivers = [to] if isinstance(to, str) else to
 

src/control_backend/schemas/internal_message.py

@@ -7,7 +7,7 @@ class InternalMessage(BaseModel):
     """
     Standard message envelope for communication between agents within the Control Backend.
 
-    :ivar to: The name of the destination agent.
+    :ivar to: The name(s) of the destination agent(s).
     :ivar sender: The name of the sending agent.
     :ivar body: The string payload (often a JSON-serialized model).
     :ivar thread: An optional thread identifier/topic to categorize the message (e.g., 'beliefs').