[no ci] versions.json,spack.yaml: Add ukmo-restricted-scope to custom-scopes rather than environment

Author: CodeGat

config/versions.json

@@ -1,5 +1,6 @@
 {
   "$schema": "https://raw.githubusercontent.com/ACCESS-NRI/schema/main/au.org.access-nri/model/deployment/config/versions/4-0-0.json",
   "spack": "1.1",
-  "access-spack-packages": "2025.07.006"
+  "access-spack-packages": "2025.07.006",
+  "custom-scopes": ["ukmo-restricted-scope"]
 }

spack.yaml

@@ -60,9 +60,3 @@ spack:
           environment:
             set:
               'SPACK_{name}_ROOT': '{prefix}'
-  config:
-    install_tree:
-      root: $spack/../restricted/ukmo/release
-    source_cache: $spack/../restricted/ukmo/source_cache
-    build_stage:
-      - $TMPDIR/restricted/spack-stage