namereg/v1 package

Canonicalize is a delegating shim to r/sys/users.Canonicalize.

HISTORY: namereg/v1 used to host its own per-stem canonical store and its own Canonicalize (l→i only). Option B unified the canonical lookup into r/sys/users keyed by full canonical name with broader substitutions ({l,i,1}→i, {0,o}→o, {-,.,_} stripped). This shim preserves the call-site name for local consumers (blacklist init, IsReserved) and any external consumer that imported the function from namereg/v1 before Option B.

New code should call susers.Canonicalize directly.