Emit an XSD-derived malli registry as Clojure source instead of one EDN file.

Every registry type becomes a .cljc namespace holding plain data defs, and a
single entry namespace requires them all, assembles the registry and the top
type, and exposes make-schema. Registry values are pure data, so per-type
files need no :require at all and a cyclic XSD type graph can never produce
cyclic namespace requires: every cross-type edge stays a keyword that malli's
registry resolves at m/schema time.

The EDN path (serialize-registry / serialize-schema) is untouched; this
namespace is purely additive.