Update EndpointConfig interfaces

[chhwang]

• Separate IB-specific options into a nested struct
• Enable connect() by an Endpoint, not only by EndpointConfig
• Other minor changes

[Copilot]

Pull Request Overview

This PR refactors the EndpointConfig interface by consolidating InfiniBand-specific configuration options into a nested Ib struct and enables connection creation directly from an Endpoint object. Key changes include storing the full EndpointConfig in Endpoint::Impl instead of individual fields, improving transport validation logic, and updating Python bindings accordingly.

Key Changes

• Refactored EndpointConfig to nest IB-specific parameters (maxCqSize, maxCqPollNum, maxSendWr, maxWrPerSend) into an EndpointConfig::Ib struct
• Modified Endpoint::Impl to store config_ instead of separate transport_, device_, and maxWriteQueueSize_ fields
• Added Communicator::connect() overload accepting const Endpoint& as the primary method, with EndpointConfig overload as a wrapper

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
include/mscclpp/core.hpp	Refactored EndpointConfig to nest IB options in Ib struct; added Endpoint::config() method; updated Communicator::connect() signature
src/include/endpoint.hpp	Changed Endpoint::Impl to store config_ instead of individual transport/device fields
src/endpoint.cc	Updated constructor and methods to use config_ member; added deserialization validation
src/context.cc	Improved transport validation with unified error message for mismatched transports
src/connection.cc	Removed redundant default maxWriteQueueSize initialization
src/communicator.cc	Refactored connect() to accept Endpoint directly; removed unnecessary std::move() calls
src/include/communicator.hpp	Removed unnecessary std::move() from future initialization
python/mscclpp/core_py.cpp	Updated Python bindings to expose nested Ib struct and modified connect() signatures

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[Binyang2014]

LGTM