Open registry mapping a node's type string to its component module.

Configuration

config :athanor,
  components: [MyApp.Components.Foo, MyApp.Components.Bar],
  fallback_resolver: {MyApp.LegacyResolver, :resolve_type}

:components is a list of modules that implement Athanor.Component. Lookup matches node["type"] against each module's metadata().type.

:fallback_resolver is an optional {module, function} tuple. When a type is not found in :components, the resolver is called as module.function(type_string) and may return a module or nil. This lets a consumer app keep its existing component dispatch wired in during a gradual migration.

Both keys are read at call time via Application.get_env/2, so test setup can swap them per scenario.