docs(changelog): record the converged located-parse and conformance work

The located-parse port, per-document %TAG scoping with tag-handle diagnostics,
and the parse-gap fixes landed on main without CHANGELOG entries, and the new
canonical event-stream conformance gate was undocumented. Record them under
Unreleased so the changelog gate passes and the release notes are complete.

CHANGELOG.md

@@ -9,6 +9,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Opt-in located parse: `parseStreamLocated` returns a source-span projection of every document,
+  each node carrying its `SourceRange` (line/column start and end) through `Model.LocatedValue` and
+  `Model.LocatedPair`. It runs alongside the plain parse without changing it, for callers that need
+  exact source positions (diagnostics, surgical fixes, language servers).
+- `%TAG` directives are now scoped per document rather than globally, and a tag shorthand whose
+  handle is not defined in its own document is diagnosed instead of silently resolved.
+- Canonical event-stream conformance gate: the parser is checked against the official yaml-test-suite
+  event (yeast) format, the strongest oracle, comparing anchors, tags, scalar styles, flow vs block,
+  and aliases for every valid case including those with no `in.json`. It ships an explicit recorded-gap
+  set (never a silent skip) and a CI workflow that fetches the suite and runs it on every push.
 - The tagged validator now enforces mapping-key uniqueness, the invariant the coverage manifest
   already claimed for `Tagged.Mapping` and `Tagged.Node` but no check enforced. `Tagged.Mapping`
   keeps every parsed pair, so a duplicate key survives into the tree; `Tagged.BuiltinCheck`
@@ -84,6 +94,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- A repeated document-end marker (`...` immediately followed by another `...`) is now accepted.
+- A root-level block scalar (`|`/`>` as the whole document) now ends at a following document marker
+  (`---`/`...`) rather than folding the marker into its content.
+- An empty explicit key in a flow mapping now parses.
 - An explicit mapping key that is only a node property (`? &e` then `: &a`) now parses as an empty
   key carrying that property, completing the empty-property-key work for the explicit-key form. The
   block parser rejected the `:` after a property-only explicit key with an `expectedNode` error;