yah-tower — rule-driven monitor on scryer (Phase 2).
This crate holds the rule engine: compiling TowerRule predicates to
ScryerFilter shapes, parsing rules from YAML/JSON, and validating rules
before they are loaded. The supervisor (F3), dispatch engine (F4), and
trigger families (F5) will live here too when those tickets land.
Architecture: .yah/docs/architecture/A052-yah-tower.md