fix: restore orchestration when agent is served

A change introduced in 91c1394 to improve how the current dialog
is passed to the orchestrator caused orchestration to stop working
when the agent is served directly.

In this scenario, current_dialog is always None because there is no
peer agent to generate a dialog.

Update __call__ to automatically build current_dialog from the
agent's memory when it is None.

Author: sergioburdisso

src/sdialog/agents.py

@@ -313,6 +313,21 @@ def __call__(self,
                 utterance = self._preprocessing_fn(utterance) if self._preprocessing_fn else utterance
                 self.memory.append(HumanMessage(content=utterance))
 
+        # Create a temporary Dialog from memory if current_dialog is not provided
+        # This allows orchestrators to work even when the agent is not served
+        if current_dialog is None and len(self.memory) > 1:
+            turns = []
+            for msg in self.memory:
+                if isinstance(msg, HumanMessage):
+                    speaker = "User"
+                elif isinstance(msg, AIMessage):
+                    speaker = self.get_name()
+                else:
+                    continue
+                turns.append(Turn(speaker=speaker, text=msg.content))
+
+            current_dialog = Dialog(turns=turns)
+
         if return_events:
             events = []
         if self._orchestrators: