Installs a per-request authz resolver via authzMiddleware and exposes
can()/decideFor()/guardPermission()/filterCan() as free functions (not
Context members, so @wrnexus/core stays free of an authz dependency).
All four route through resolver.decide(), never permissionsFor(), so
resource-scoped policy denials can't be bypassed via the coarse
permission set. Per-request results are memoised keyed on (permission,
resource) to avoid re-hitting the store within a request without
leaking one resource's verdict onto another.
Clintchiz
984c6236d3