Add CoinEx cryptocurrency exchange MCP server

[helix-song]

Description

This PR adds the CoinEx MCP Server to the official Model Context Protocol servers directory. The CoinEx MCP Server is an official integration that enables AI agents to interact with the CoinEx cryptocurrency exchange through a standardized MCP interface.

Server Details

• Server: coinex-mcp-server
• Changes to: Add new server entry to the servers directory

Motivation and Context

The CoinEx MCP Server provides AI agents with comprehensive access to CoinEx exchange functionality, including:

• Market data queries (spot and futures markets)
• K-line/candlestick data retrieval
• Order book depth information
• Account balance queries (with authentication)
• Order placement and management
• Futures-specific data (funding rates, liquidation history, margin tiers, etc.)

This integration allows users to leverage AI agents for cryptocurrency trading analysis, market monitoring, and automated trading operations through Claude and other MCP-compatible clients.

How Has This Been Tested?

The server has been tested with:

• Claude Desktop client via stdio transport
• HTTP/SSE transport modes
• Public market data endpoints (no authentication required)
• Authenticated trading endpoints (with API credentials)
• Both spot and futures market operations

Breaking Changes

None. This is a new server addition to the directory with no impact on existing servers.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

• Official Streamable HTTP Service: https://mcp.coinex.com/mcp
• Repository: https://github.com/coinexcom/coinex_mcp_server
• PyPI: https://pypi.org/project/coinex-mcp-server/
• Official CoinEx API Documentation: https://docs.coinex.com/api/v2
• Supports multiple transport protocols: stdio (default), HTTP, SSE
• Flexible credential handling: environment variables or HTTP headers
• Comprehensive tool set for both market data and trading operations

[olaservo]

Thanks for your contribution to the servers list. This has been merged in this combined PR: #2974