SPARQL UPDATE queries add standard vocabulary properties alongside
existing custom predicates: schema:Person/Place/Organization types,
schema:givenName/familyName/birthDate, owl:sameAs for authority links,
wgs84:lat/long for coordinates, skos:Concept/prefLabel for enumerations,
and rdfs:label for persons.
19 queries in updates/ convert categorical columns (continent, country,
city, gender, profession, etc.) from literals to typed RDF objects with
rdfs:label. map/step-02.rb applies them to produce data/graph-02.ttl.
Also fix step-01.rb to sanitize column names with spaces and avoid
prefix serialization issues with fragment IRIs.
