Rule engine core: fact model, working memory, matching primitives, agenda, sessions

Rule engine compiler: RuleDefinition -> CompiledRuleSet

Rule engine CEL: the §6.4 expression escape hatch, backed by dev.cel

Rule engine observability: tracing and Flight Recorder listeners

Rule engine schema: the optional FactSchemas of §2.3, backed by JSON Schema

Rule engine testkit: fixtures, the firing-sequence oracle, shuffle-determinism harness, JMH benchmarks