ubuntu-server-01 (10.40.40.2) runs Portainer itself and is already
managed via local Docker socket (Portainer endpoint ID=3). Deploying
a Portainer Agent there is redundant and port 9001 binding fails.
Add portainer_skip_agent: true flag to the inventory and check it in
both Play 2 (deploy agent) and Play 3 (register endpoint) to exclude
the host from agent-based enrollment.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>