The two monolithic XSD content/identity rules only satisfied the OpenAPIKit
validation idiom at the wrong granularity: no per-constraint removability,
no isolable failing/near-miss tests. Split them into 32 named rules, each
finding tagged at its origin and cached per XSDContext so the walk still
runs once per document (the #101 decision against duplicating XSD's
recursive type resolution still holds). Wired the streaming path's ID/IDREF
and identity checks through the same framework instead of calling the
validators imperatively, and added the unwrapAndLookup combinator the rule
already named as required.
Also includes the mandated repo-wide swiftformat/swiftlint pass.
Resolver(sgml:) parses the legacy SGML catalog format: PUBLIC, SYSTEM,
DELEGATE, CATALOG, BASE, and OVERRIDE entries with -- comment --
delimiters. Replacement URIs resolve against BASE and the supplied
baseURI; OVERRIDE YES/NO maps to the prefer-public fallback. Unknown
keywords are skipped tolerantly. Feeds the same Resolver as the XML
catalog.
Part of #86
