feat(cli): add configuration for server customization ordering (#6179)

This adds a configuration option in `HttpConfig` that allows LangGraph
Platform users to apply custom authentication hooks before (other)
custom middleware. Currently, the order is fixed (custom middleware is
always evaluated before custom auth).

(Apologies for the noise in
[de187a9](https://github.com/langchain-ai/langgraph/pull/6179/commits/de187a989e807c5687c22db1fc065d24030fa6b7),
apparently from the forced application of new linter rules.)

libs/cli/langgraph_cli/config.py

@@ -18,6 +18,7 @@ DEFAULT_IMAGE_DISTRO = "debian"
 
 
 Distros = Literal["debian", "wolfi", "bullseye", "bookworm"]
+MiddlewareOrders = Literal["auth_first", "middleware_first"]
 
 
 class TTLConfig(TypedDict, total=False):
@@ -359,6 +360,17 @@ class HttpConfig(TypedDict, total=False):
     agent's behavior or permissions on a request's headers."""
     logging_headers: Optional[ConfigurableHeaderConfig]
     """Optional. Defines which headers are excluded from logging."""
+    middleware_order: Optional[MiddlewareOrders]
+    """Optional. Defines the order in which to apply server customizations.
+
+    Choices:
+      - "auth_first": Authentication hooks (custom or default) are evaluated
+      before custom middleware.
+      - "middleware_first": Custom middleware is evaluated
+      before authentication hooks (custom or default).
+
+    Default is `middleware_first`.
+    """
 
 
 class Config(TypedDict, total=False):