Pre-shared keys for WireGuard remote access

When you create a WireGuard remote-access server on a plant, "Require a pre-shared key" is on by default: the connected site gets a generated key on top of its keypair, shown once after creation. For an existing connection, "Include a pre-shared key" adds, renews or removes the key when you regenerate its configuration.

• The edit dialog shows whether a connection uses a pre-shared key.
• Both ends of the tunnel must use the same key; the downloaded configuration carries it once.
• OpenVPN connections are unchanged.