Function parse_rule_yaml 

pub fn parse_rule_yaml(src: &str) -> Result<TowerRule, ParseError>

Parse a YAML rule definition into a TowerRule.

Operators write rules in .yah/cloud/rules/<name>.yaml. The YAML must deserialize into a valid TowerRule; use validate afterwards to catch semantic errors (e.g. missing agent_class on an AgentDispatch trigger).