fix: agent-core test failures in session_manager and message_bus

- session_manager: add session to _local_cache in create_session()
  so get_session() and get_active_sessions() work without Redis/Postgres
- message_bus: use asyncio.create_task() in request() for publish
  so handler runs concurrently and timeout actually fires

All 76 tests pass now.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

agent-core/orchestrator/message_bus.py

@@ -345,11 +345,19 @@ class MessageBus:
         self._pending_responses[message.correlation_id] = future
 
         try:
-            # Publish the request
-            await self.publish(message)
+            # Publish as task so handler runs concurrently (enables timeout)
+            publish_task = asyncio.create_task(self.publish(message))
 
-            # Wait for response
-            return await asyncio.wait_for(future, timeout)
+            # Wait for response with timeout
+            try:
+                return await asyncio.wait_for(future, timeout)
+            finally:
+                if not publish_task.done():
+                    publish_task.cancel()
+                    try:
+                        await publish_task
+                    except (asyncio.CancelledError, Exception):
+                        pass
 
         except asyncio.TimeoutError:
             logger.warning(

agent-core/sessions/session_manager.py

@@ -250,6 +250,7 @@ class SessionManager:
             "user_id": user_id
         })
 
+        self._local_cache[session.session_id] = session
         await self._persist_session(session)
 
         logger.info(
@@ -302,6 +303,7 @@ class SessionManager:
         """
         session.heartbeat()
         self._local_cache[session.session_id] = session
+        self._local_cache[session.session_id] = session
         await self._persist_session(session)
 
     async def delete_session(self, session_id: str) -> bool: