LocalDbSyncService never read request headers, so setting
LocalDb:Replication:ApiKey on both nodes left the passive endpoint open
(LocalDb-001). It now requires Authorization: Bearer <key> (constant-time)
before the handshake and before newest-wins takeover, refusing anything else
with Unauthenticated. A blank key keeps the old accept-all behaviour and
logs a startup warning. Wire-compatible: the initiator has always sent the
header when the key is set; ScadaBridge/OtOpcUa interceptors use the same key.
LocalDb 0.3.5 -> 0.3.6 (unpublished).
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty
48813bba6f