Convert one of the three existing Lua AIs in 'Guardians' (return guardian, stationed guardian or coward) to a Micro AI and document it on the Wesnoth wiki. The current AI requires the definition of a Lua engine and candidate actions if a campaign author wants to include it in a scenario. By contrast, Micro AIs can be included in a scenario very easily with a single WML tag, [micro_ai], such as

[micro_ai]
    side=2
    ai_type=guardian
    action=add
[/micro_ai]

The goal of this task is to set up the Micro AI syntax for the existing AI, so that it can be activated in the existing scenario with this tag.

Examples of two micro AIs already exist and can be used as models for this task. Documentation about Micro AIs in general and detailed instructions for this task are available on the Wesnoth wiki.