ping and identify

[turuslan]

• ping protocol
• identify protocol
• fix quic incoming connection address
• some changes from gossip #6

[Copilot]

Pull Request Overview

This PR implements ping and identify protocols for libp2p, along with a fix for QUIC connection address handling. It adds two core libp2p protocols that enable peer connectivity testing and peer information exchange.

• Implements ping protocol for peer connectivity testing with configurable timeout and interval
• Implements identify protocol for exchanging peer information including addresses and supported protocols
• Fixes QUIC incoming connection address resolution to use actual peer endpoint

Reviewed Changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/transport/quic/engine.cpp	Fixes QUIC connection to use actual peer socket address instead of remote address from operation
src/protocol/ping.cpp	Implements ping protocol with echo functionality and periodic ping operations
src/protocol/identify/identify.proto	Defines protobuf schema for identify protocol messages
src/protocol/identify/identify.cpp	Implements identify protocol for peer information exchange
src/protocol/identify/CMakeLists.txt	Build configuration for identify protocol
src/protocol/CMakeLists.txt	Build configuration for ping protocol
src/host/basic_host.cpp	Changes constructor parameters from unique_ptr to shared_ptr and adds new methods
src/CMakeLists.txt	Links new protocol libraries
include/libp2p/protocol/ping.hpp	Header for ping protocol implementation
include/libp2p/protocol/identify.hpp	Header for identify protocol implementation
include/libp2p/peer/protocol.hpp	Simplifies protocol name type definitions
include/libp2p/host/basic_host.hpp	Updates method signatures for shared_ptr usage
include/libp2p/coro/yield.hpp	Utility for coroutine thread switching
include/libp2p/common/weak_macro.hpp	Macros for weak pointer handling
include/libp2p/common/protobuf.hpp	Utilities for protobuf encoding/decoding
include/libp2p/basic/write_varint.hpp	Utility for writing varint-prefixed messages
include/libp2p/basic/read_varint.hpp	Utility for reading varint-prefixed messages
include/libp2p/basic/encode_varint.hpp	Utility for varint encoding

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