The ported engine wins every conflict: main's post-fork patches to the
hand-rolled Scanner and TokenEventParser land on deleted files and are
dropped; their behaviors are carried by the port and guarded by the
whole-suite conformance gate (402/402 passing).
Merge adaptations, all gates green (style, namespacing, forbidden
patterns, changelog, roadmap, swiftformat, swiftlint strict, build,
full test suite, whole-suite conformance sweep):
- PureYAMLJSON representability rules move onto the Check algebra,
replacing the retired legacy Rule type.
- The permissive tag-handle pre-pass is removed; the port rejects an
undefined handle at parse time (suite case QLJ7) and the validation
report carries it as a parse diagnostic.
- EventStreamComposer's nested types split one-per-file per the
namespacing gate.
- Tests pinned to old-engine behavior were re-verified against the
reference and updated: libyaml rejects an explicit-key continuation
ending at a value colon, and suite case QB6E requires rejecting a
quoted continuation at column 0.
- CHANGELOG unreleased entries from both lines are preserved in two
groups with a provenance note.
Closes#1, closes#3
A block implicit key must lie on a single line, so a quoted scalar whose
opening and closing quotes sit on different lines cannot be one. The
scanner synthesized the implicit key regardless, so '"c\n d": 1' and the
single-quoted form parsed as a mapping with a folded key.
When synthesizing the implicit key for a quoted scalar followed by ':',
the scanner now rejects the construct if the scalar spanned a line break.
The restriction is block-only: a flow mapping key may span lines, so the
check is gated on block context, and a multiline quoted value, a single-
line quoted key, and an explicit key (which carries no ':' directly after
the scalar) are all unaffected.
Measured against the official YAML test-suite, parse-level conformance
rises from 261/333 (78.4%) to 264/333 (79.3%) with no regression.
