Phase 1 of the integration plan modifies alknet-core to support the
architectural changes from Phase 0 ADRs and specs. Decomposed into
dependency-ordered tasks across config split, identity, forwarding
policy, OperationEnv, interface abstraction, and NAPI reload API.
Critical path: config-split → identity → forwarding → wire-into-handler
→ interface-trait → ssh-interface-extraction → review.
Two highest-risk tasks (interface-trait-definition, ssh-interface-extraction)
are split from §1.8 per the integration plan's note that it may need
sub-phases. OperationEnv is split into types and runtime per Phase 1
local-dispatch-only constraint.
