phosphor-window-rules

Phosphor's single window-rule engine: one composable match-expression language, one pluggable action set, one serialization format, and one evaluation pipeline with a match cache. Both the KWin effect and the daemon link this one implementation so match code lives in exactly one place. RuleEvaluator::resolve() walks the rule set in descending priority and accumulates the first action that fills each slot, and WindowRuleSet reads and writes windowrules.json at a fixed schema version, dropping malformed rules with a diagnostic.