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.
Add a canonical11 preset / mergeInheritedBase option. On a document subset,
the omitted-ancestor xml:base chain is merged into the apex by RFC 3986
reference resolution (vs 1.0 nearest-wins), the apex's own relative xml:base
is resolved against it, and xml:id is no longer inherited; xml:lang/xml:space
still inherit nearest. A self-contained RFC 3986 resolver (parse, path merge,
dot-segment removal) backs the merge, with tests covering the 1.1-vs-1.0
difference, dot segments, xml:id, and lang/space.
Part of #105 (Tier 3)
