ansible: fix deprecated yaml callback plugin

Use result_format=yaml with builtin default callback instead of
the removed community.general.yaml plugin.

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

ansible/ansible.cfg

@@ -7,9 +7,10 @@ host_key_checking = False
 forks = 10
 pipelining = True
 
-# Output formatting
-stdout_callback = yaml
+# Output formatting (YAML output via builtin default callback)
+stdout_callback = default
 callbacks_enabled = profile_tasks
+result_format = yaml
 
 [ssh_connection]
 # Reuse SSH connections