Macro pack_runtime_metadata 

macro_rules! pack_runtime_metadata {
    () => { ... };
}

Delegate every const-backed PackRuntime metadata accessor to Self: Pack.

Invoke once inside impl PackRuntime for MyPack as khive_runtime::pack_runtime_metadata!();. It emits name, note_kinds, entity_kinds, brain_consumer_kinds, handlers, edge_rules, entity_types, requires, note_kind_specs, note_embedding_policies, schema_plan and schema_column_additions. Do not also implement those methods manually.

A missing Pack::SCHEMA_PLAN becomes SchemaPlan::empty(). Validation rule values remain explicit because Pack::VALIDATION_RULES contains only ids.