Malli value objects for the OPAQUE addon wire — the contract between a host
proxying an IAddon and the out-of-process kernel that really implements it.

Shapes are uncompiled malli DATA (house idiom: PascalCase defs) seeded into a
LOCAL composite registry that COMPOSES hive-addon.schema's registry — the
AddonId/AddonType/CapabilitySet value objects are reused, never redefined.
The registry is NEVER installed as the malli global default; reach it via
`schema`/`validate`/`explain`/`validate*` or by passing {:registry registry}.

Opaque shapes are registered under :opaque/* keys (:opaque/wire,
:opaque/request, :opaque/response, :opaque/describe, :opaque/spec).

The kernel side never loads this namespace: hive-addon.opaque.codec and
hive-addon.opaque.serve are malli-free so a cljw-built binary carries no
schema runtime. These schemas are the host-side single source the m/=>
contracts (hive-addon.opaque.contracts) and the generated tests read.