Protocol sniffing adds CPU overhead per new connection

When Istio cannot determine the protocol on a port, it falls back to TCP protocol sniffing which requires reading the first few bytes of each connection. This sniffing operation consumes CPU for every new connection until protocol is detected.

Declare protocols explicitly using port name prefixes in Service definitions. Use http- prefix for HTTP ports (e.g., http-api), grpc- for gRPC ports (e.g., grpc-internal), and tcp- for TCP ports (e.g., tcp-data). This tells Istio the protocol immediately, skipping the detection step entirely.