Add opaque-ke (v4, ristretto255) for password-based registration and
login. Extend NodeService schema with opaqueRegisterStart/Finish and
opaqueLoginStart/Finish RPCs. Add Store trait methods for OPAQUE server
setup and user records. Initial e2e integration test scaffolding.
Note: FileBackedStore does not yet implement the new Store trait
methods — server compilation is temporarily broken.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Christian Nennemann
8d5c1b3b9b