Empty API_TOKEN disables authentication on network-reachable HTTP/SSE transport

Nocturne Memory is a lightweight, rollbackable, and visual Long-Term Memory Server for MCP Agents. Prior to 2.4.1, when API_TOKEN is unset or empty, the BearerTokenAuthMiddleware bypasses authentication for all HTTP requests. Combined with the default 0.0.0.0 host binding and CORS allow_origins=["*"], operators following the Docker setup without explicitly setting API_TOKEN expose the full Knowledge-Graph read/write API to any LAN-reachable client. An attacker on the same network can read, write, or delete all memory entries — including system://boot and core://* URIs that auto-load into downstream agent sessions, enabling persistent prompt-injection. This vulnerability is fixed in 2.4.1.