Namespaced `TagResolver` API

For situations where users may want to have multiple sources contribute to a TagResolver, it may make sense to have identify tags by Key rather than just a plain value.

This would have a default namespace, for example adventure, and other namespaces could be registered.

The API would look something like:

interface TagResolver {
  interface NamespacedBuilder {
    self defaultNamespace(String);
    self namespaceResolver(String namespace, TagResolver resolver);
    self tag(Key tag, Tag);
    self tag(Key tag, BiFunction<ArgumentQueue, Context, Tag> factory);
    TagResolver build();
  }
}

This would allow platforms to collect custom tags that could safely be made available globally.

Start by locating the existing TagResolver API and its builder implementation, then review how tags, Key values, ArgumentQueue, and Context are currently represented. Compare those entry points with the proposed NamespacedBuilder, and consider the work complete when multiple namespaces can safely contribute tags through the documented API.