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 the PureXML.Pattern namespace: a compiler for the streamable XPath
subset (names, *, prefix:*, /, //, leading absolute /, trailing @attr) into
a Matcher, with predicates and . / .. rejected. The backward-matching
algorithm tests an element's ancestor-or-self path. Pattern.matches(_:in:)
streams a document through the pull parser and returns matching node paths
in document order from the open-element stack alone, no tree built.
Closes#44Closes#45Closes#22
