Add namespace prefixes (rdfs, migrants, person, personp, work, workp,
location, locationp) to query files. Use --prettify in Rake tasks so
example files use abbreviated IRIs. Fix 2hop task to use graph-02.
SPARQL queries to list classes and properties, and src/schema.rb
CLI to run them against any graph file. Includes bundler/setup
for compatibility with Ruby 4.0 without bundle exec.
