describe() now carries each namespace's detached composition base and raw
user section beside the resolved value — presence in the user layer is how
a form marks a field user-overridden — and describe({redactSecrets:true})
strips role('secret') fields from every layer while enumerating their
{path,set} slots, so a wire surface has no slot that can carry a secret.
The pure redactSecrets(schema,value) walker (object/dict/array containers,
secret-role subtree as opaque leaf, inputs never mutated) is exported for
any other wire; the README's no-redaction Known Limitation is discharged.