Split the six files that declared multiple sibling types under one
namespace extension so each file declares exactly one top-level type:
the Tagged node component types (Node, NodeKind, Scalar, Sequence,
Mapping, Pair), the validation report types (Report, Source,
SourceReport, BatchReport), DiagnosticKind, TokenKind, ScannerFlowContext
kind, and the event-stream composer helpers. Public type names are
unchanged; the shared report-rendering helpers move from file-private to
internal so the split report types still reach them.
Make check-namespacing.sh namespace-aware: the previous column-anchored
scan was blind to types declared inside indented extension blocks, so it
passed while the rule was violated. It now counts direct members of a
PureYAML namespace extension and ignores nested types and private helpers.
Mirror the shared Swift rules canon (rules-swift, commit 4ebb892) into
docs/rules-swift/ as a read-only reference alongside the repo's tailored
docs/rules/. PROVENANCE.md records the source, commit, and what was
included or excluded; the upstream repo's own VCS, CI, and lint tooling
is omitted as machinery rather than rule content.
Exclude the vendored tree from the style gate (scripts/check-style.sh)
and the pre-commit hook: the canon's enforcement docs quote the
forbidden attribution phrases to define them, the same reason the
repo's own enforcement files are already excluded.
Add structured validation diagnostics, JSON and Yams comparison gates, and lazy token/event parsing so production behavior is measured without retaining full intermediate parser arrays.
