Refactor `ProtoClient` into a transport-agnostic base class and introduce TCP...

Refactor ProtoClient into a transport-agnostic base class and introduce TCP and Reliable-UDP implementations

• Refactor ProtoClient into an abstract base class handling common protobuf framing, varint header decoding, and receive-buffer management.
• Introduce ProtoTCPClient to encapsulate legacy NIO selector-based TCP transport logic.
• Introduce ProtoUDPClient providing a reliable-UDP transport implementation with handshake (SYN/ACK), retransmission, and cumulative acknowledgment support, matching ESP8266 firmware behavior.
• Standardize the ProtocolDispatcher interface and lifecycle callbacks (fireOnConnected, fireOnError, etc.) across transport types.
• Update ProtoClientDynamicReceiveBufferSizeMax to extend ProtoTCPClient to maintain legacy compatibility.
• Relocate and optimize utility methods for hex conversion and stack trace formatting within the base class.