ForwardingAction, TargetPattern, ForwardingRule, OperationType,
InterfaceConfig, InterfaceKind, DynamicConfig, and CallError are all
likely to gain variants/fields in future phases. Marking them
#[non_exhaustive] now prevents downstream breakage when new
variants/fields are added. Added constructor methods for types that
are constructed from other crates.
Review found Phase 1 approved with minor issues. Created cleanup tasks:
- napi-identity-provider-wiring (bug: NAPI bypasses IdentityProvider)
- panic-free-static-config (code smell: panic/unwrap in production path)
- non-exhaustive-public-api (future-proofing public API types)
- adr-doc-comments (doc convention: ADR references in new modules)
- ssh-session-recv-stub-doc (documentation: mark stubs as planned)
