[google-cloud-ces] Generation fails on google/cloud/ces/v1beta due to Service resource namespace collision #18888

Description

Regenerating google-cloud-ces (google/cloud/ces/v1beta) with the latest googleapis sources (646596e286b464ca2c2cca6f4c767e7c19046489, specifically cl/1005071734) fails during librarian generate --all with a ValueError in protoc-gen-python_gapic:

ValueError: 

Fatal: Namespace collision detected for resource type 'Service'.
Resources 'agentregistry.googleapis.com/Service' and 'servicedirectory.googleapis.com/Service' both flatten to the exact same method name.
To protect backward compatibility, explicitly alias one of these using the `--resource-name-alias` CLI parameter.
Example: --resource-name-alias=servicedirectory.googleapis.com/Service:CustomName

--python_gapic_out: protoc-gen-python_gapic: Plugin failed with status code 1.

Root Cause

google/cloud/ces/v1beta now references both agentregistry.googleapis.com/Service and servicedirectory.googleapis.com/Service, which both flatten to service_path(...) in the Python GAPIC generator unless --resource-name-alias is configured in librarian.yaml (opt_args_by_api).

Temporary Workaround

To unblock this week's Wednesday googleapis API sources update across the rest of the monorepo, skip_generate: true has been set on google-cloud-ces in librarian.yaml referencing this issue.