Server-side implementation landed on Dankclaw: dedicated 'tunnel' account (nologin shell, password-locked, key-only auth), sshd drop-in 99-tunnel.conf scoping AllowTcpForwarding to that user with PermitTTY off, and permitopen="localhost:8787" key-option guidance so a leaked tunnel key can only forward to the webui port. WebUI stays loopback-only published.