feat(custom-fields) : filter machineContextOnly from standalone and machine-detail views

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/app/composables/useEntityCustomFields.ts

@@ -45,7 +45,7 @@ export function useEntityCustomFields(deps: EntityCustomFieldsDeps) {
         definitionSources.value,
         entity().customFieldValues,
       ),
-    ),
+    ).filter((field: any) => !field.machineContextOnly && !field.customField?.machineContextOnly),
   )
 
   const candidateCustomFields = computed(() =>