ORAX AiTM - SignalR negotiate handshake to random-subdomain lookalike host

This rule detects potential Adversary-in-the-Middle (AiTM) activity by monitoring for a two-stage pattern: a SignalR negotiation POST request followed by a WebSocket upgrade request to a suspicious domain structure. The pattern specifically targets lookalike domains featuring a random subdomain of at least 12 alphanumeric characters, which is indicative of ORAX-style AiTM infrastructure.