- sweep idle sessions (SESSION_TTL_MIN, default 30 min) and cap concurrent
  sessions per key and globally — the registry could previously grow unboundedly
- bind 127.0.0.1 by default (HOST env to override) — run behind a TLS proxy
- bind sessions to the API key that opened them
- refuse to start without TONNODE_KEYS unless TONNODE_ALLOW_OPEN=1
- reject JSON-RPC batch arrays so one request can't multiply liteserver load
- 400 for malformed JSON, 413 for oversized bodies, 404 for unknown sessions
- generic 500 body, internals go to the server log; nosniff/no-store headers
- graceful SIGTERM/SIGINT shutdown; per-request log lines with key prefixes
- don't cache a failed liteclient init forever (lite.ts)
- deploy/: systemd unit, env template and Caddyfile for mcp.tonnode.io