Agent Skills: ring:using-assert

Using lib-observability/assert, Lerian's runtime assertion package, in two modes. Sweep Mode detects panic()/log.Fatal zero-panic violations, DIY invariant checks, hand-rolled domain predicates, and missing InitAssertionMetrics. Reference Mode catalogs the asserter lifecycle, domain predicates, observability trident, AssertionError unwrapping, and the panic-vs-assert-vs-error decision tree. Go-only. Skip for non-Go or frontend code.