NEO-65: Replace deprecated RefResolver with referencing.Registry.

Use jsonschema 4.22+ registry API for cross-file recipe schema $ref
resolution (Bugbot PR #99).

scripts/validate_content.py

@@ -18,8 +18,8 @@ import json
 import sys
 from pathlib import Path
 
-import jsonschema
 from jsonschema import Draft202012Validator
+from referencing import Registry, Resource
 
 REPO_ROOT = Path(__file__).resolve().parent.parent
 SKILL_SCHEMA = REPO_ROOT / "content/schemas/skill-def.schema.json"
@@ -576,9 +576,13 @@ def _recipe_def_validator() -> Draft202012Validator:
     """Build a validator that resolves recipe-def $ref to recipe-io-row schema."""
     io_schema = json.loads(RECIPE_IO_ROW_SCHEMA.read_text(encoding="utf-8"))
     def_schema = json.loads(RECIPE_SCHEMA.read_text(encoding="utf-8"))
-    schema_store = {io_schema["$id"]: io_schema, def_schema["$id"]: def_schema}
-    resolver = jsonschema.RefResolver.from_schema(def_schema, store=schema_store)
-    return Draft202012Validator(def_schema, resolver=resolver)
+    registry = Registry().with_resources(
+        [
+            (def_schema["$id"], Resource.from_contents(def_schema)),
+            (io_schema["$id"], Resource.from_contents(io_schema)),
+        ]
+    )
+    return Draft202012Validator(def_schema, registry=registry)
 
 
 def _prototype_slice3_recipe_gate(