feat(auth): bring opaque (RFC 9807) auth

OPAQUE (RFC 9807) implementation (using `opaque-ke` crate)

    with opaque authentfication, server will never receive the password (in the auth=password mode)
    this is a must have to create trust with users to permit end to end encryption in the future
    (we cannot know if user use the same password/passphrase for his asymetric key or his oxicloud auth,
    this is why server must never have the password)

    pass1: prepare server

tests/api/opaque_substrate.hurl

@@ -0,0 +1,76 @@
+# =============================================================
+# OxiCloud — OPAQUE aPAKE (Phase 0 substrate) — inertness smoke
+# =============================================================
+# The full OPAQUE handshake is NOT testable in Hurl (every message
+# contains session-random OPRF blinding + AKE nonces that can't be
+# hardcoded in a .hurl body). Full-flow assertions belong in a Rust
+# integration test using `opaque-ke` client-side against a real
+# server. That lands with the Phase 1 endpoints.
+#
+# What THIS file asserts is the substrate-level contract for Phase 0:
+#
+#   1. The server booted with the OPAQUE substrate loaded — proved
+#      transitively by the fact that this suite reached the
+#      `--test-report` stage at all. `tests/common/server.env` sets
+#      `OXICLOUD_OPAQUE_MODE=migrate` + a persisted `SERVER_SETUP`;
+#      a boot failure (bad base64, missing setup, ciphersuite drift)
+#      would 500 every request or refuse to bind the port.
+#
+#   2. The Phase 1 endpoints are not yet routed. An unauthenticated
+#      POST to any `/api/*` path returns **401** (not 404) — the
+#      `/api` namespace is behind the auth middleware, so a missing
+#      route is indistinguishable from "route exists but needs
+#      auth". That's deliberate anti-enumeration: attackers can't
+#      probe which endpoints exist.
+#
+#      When Phase 1 ships:
+#         - Register endpoints stay 401 unauth (they'll be
+#           session-required — anti-enum still applies).
+#         - Login KE1 / KE3 will flip to **400** because they'll be
+#           public and reject the placeholder payloads below as
+#           malformed. That's the natural regression signal: update
+#           this file to hit the endpoints with a valid handshake
+#           driven from a Rust integration test.
+#
+#   3. The legacy `POST /api/auth/login` continues to work under
+#      Migrate mode. `auth_login.hurl` asserts this thoroughly; we
+#      don't duplicate it here.
+# =============================================================
+
+# ─────────────────────────────────────────────────────────────
+# Case 1 — Register-start endpoint not routed (401 anti-enum).
+# ─────────────────────────────────────────────────────────────
+POST {{base_url}}/api/auth/opaque/register/start
+Content-Type: application/json
+{ "registrationRequest": "unused-phase-0" }
+
+HTTP 401
+
+# ─────────────────────────────────────────────────────────────
+# Case 2 — Register-finish endpoint not routed (401 anti-enum).
+# ─────────────────────────────────────────────────────────────
+POST {{base_url}}/api/auth/opaque/register/finish
+Content-Type: application/json
+{ "registrationRecord": "unused-phase-0", "ciphersuiteVersion": 1 }
+
+HTTP 401
+
+# ─────────────────────────────────────────────────────────────
+# Case 3 — Login KE1 endpoint not routed (401 anti-enum).
+#           Will flip to 400 in Phase 1 (public + malformed body).
+# ─────────────────────────────────────────────────────────────
+POST {{base_url}}/api/auth/opaque/login/ke1
+Content-Type: application/json
+{ "userIdentifier": "{{username}}", "startLoginRequest": "unused-phase-0" }
+
+HTTP 401
+
+# ─────────────────────────────────────────────────────────────
+# Case 4 — Login KE3 endpoint not routed (401 anti-enum).
+#           Will flip to 400 in Phase 1 (public + malformed body).
+# ─────────────────────────────────────────────────────────────
+POST {{base_url}}/api/auth/opaque/login/ke3
+Content-Type: application/json
+{ "exchangeId": "unused-phase-0", "finishLoginRequest": "unused-phase-0" }
+
+HTTP 401

tests/api/run.sh

@@ -146,6 +146,7 @@ log "Running Hurl tests..."
 hurl --variables-file "$API_DIR/test.env" --file-root "$REPO_ROOT/tests" --test --jobs 1 \
   "$API_DIR/setup.hurl" \
   "$API_DIR/auth_login.hurl" \
+  "$API_DIR/opaque_substrate.hurl" \
   "$API_DIR/user_ui_preferences.hurl" \
   "$API_DIR/auth_session_lifecycle.hurl" \
   "$API_DIR/auth_magic_link_login.hurl" \