Upgrade Core to 4e9d280a8a452885c7cd2bc488799a4f6410f4d8

[jviotti]

Signed-off-by: Juan Cruz Viotti jv@jviotti.com

[augmentcode]

🤖 Augment PR Summary

Summary: Updates the vendored sourcemeta/core dependency to commit 4e9d280a8a45…, bringing in SchemaFrame improvements and JSON Pointer container support changes.

Changes:

• Bumped the core SHA in DEPENDENCIES and synced the corresponding vendored sources.
• Removed the std::hash specialization for JSON Pointers; added explicit Pointer::Hasher/Comparator (including reference-wrapper support) for unordered containers.
• Added fast pointer-based lookups in SchemaFrame via an internal pointer→locations cache and a new traverse(pointer, LocationType) overload.
• Extended location metadata with an orphan flag and included it in SchemaFrame::to_json() output.
• Implemented reachability analysis (SchemaFrame::is_reachable) to determine which locations could be evaluated during validation.
• Updated schema transformer traversal to use the explicit pointer hasher for visited sets.
• Adjusted AlterSchema rules: OrphanDefinitions now uses reachability to remove only truly unreachable definitions; EmptyObjectAsTrue no longer forces a reframe after transforming.

Technical Notes: SchemaFrame is now non-copyable/non-movable to prevent internal cache dangling; instantiate per analysis and pass by reference where needed.

_{🤖 Was this summary useful? React with 👍 or 👎}

[augmentcode]

Review completed. No suggestions at this time.

Comment augment review to trigger a new review at any time.