Summary

Fixes #85 — importing the Brick ontology failed with RDF parse error: No ontology metadata or OWL classes found in the RDF document.

Root cause: the parser only recognizes typed node elements (<owl:Class rdf:about="...">). Brick's official RDF/XML (and the output of Python's rdflib generally) declares resources exclusively in the equivalent rdf:Description form:

<rdf:Description rdf:about="https://brickschema.org/schema/Brick#AHU">
  <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#Class"/>
  ...
</rdf:Description>

Brick 1.4 contains 0 typed <owl:Class> elements and 1,532 classes declared via rdf:type — so the parser found nothing and threw.

Changes

• getTypedElements() (new helper in src/lib/rdf/parser.ts): collects both syntaxes for owl:Ontology, owl:Class, owl:DatatypeProperty, and owl:ObjectProperty. Both RDF/XML forms are semantically identical per the spec, and downstream child-element reading (rdfs:label, rdfs:domain, …) is unchanged.
• Turtle detection: brickschema.org's default download is .ttl; that input previously produced Malformed XML: …. Content starting with @prefix/@base now gets a clear, actionable error (convert to RDF/XML first).
• Perf drive-by: the DataBinding scan iterated the live getElementsByTagName('*') collection by index — quadratic in some DOM implementations (measured 3m30s for Brick's ~500k elements under jsdom). Swapped for a static querySelectorAll('*') snapshot (no mutation occurs during the loop): same semantics, linear time.

Validation

• npx tsc --noEmit — clean
• npx vitest run — 24 files, 401/401 tests pass (9 new: rdf:Description extraction for all four types, mixed-syntax dedupe, Turtle detection)
• Real-world check: Brick 1.4 RDF/XML (5.3 MB, fetched via content negotiation from brickschema.org) now parses to 1,530 entity types, ontology name Brick, in ~8s under jsdom (previously: error after 3m35s)

Notes

• Rendering a 1,530-node graph is a separate concern (tracked by the navigation items in Usability issues #87); this PR makes the import succeed per RDF parse error #85.
• Relationship extraction yields 0 for Brick because its object properties don't carry rdfs:domain/rdfs:range pairs the current mapper uses — faithful to current behavior, could be a follow-up.