A functional toolkit for authoring resource-leveling algorithms — compose constraint and scoring blocks, enumerate feasible schedules

docs: document the declarative run layer; fix stale OpenUnitPenalty example master

README gains a 'Declarative runs (RunConfig)' section covering the versioned registry, analyzeRun, enabled levers, weighted/lexicographic objectives, shared profiles, and provenance; the OpenUnitPenalty example now matches the current unitIds schema. CHANGELOG entries added.