Confirm sys.path includes current dir for app serve (#12851)

- Make sure sys.path is set properly for langchain app serve
- bump

libs/cli/langchain_cli/namespaces/app.py

@@ -4,6 +4,7 @@ Manage LangChain apps
 
 import shutil
 import subprocess
+import sys
 from pathlib import Path
 from typing import Dict, List, Optional, Tuple
 
@@ -219,6 +220,9 @@ def serve(
     Starts the LangServe app.
     """
 
+    # add current dir as first entry of path
+    sys.path.append(str(Path.cwd()))
+
     app_str = app if app is not None else "app.server:app"
     host_str = host if host is not None else "127.0.0.1"