feat: add CLI arguments support for better MCP client compatibility

[alfonsodg]

Problem

GitHub Copilot CLI v1.2.0 has a known bug where environment variables in MCP server configurations are not properly passed to the server process. This affects MiniMax-MCP and other MCP servers that rely on environment variables for configuration.

Issue: When configured with env block, the server starts but cannot access API keys or other configuration values, causing authentication failures.

Solution

This PR adds CLI argument support as an alternative configuration method that works reliably across all MCP clients, including GitHub Copilot CLI.

Changes

• Added CLI argument parser for --api-key, --base-path, --api-host, --resource-mode
• CLI arguments take precedence over environment variables
• Updated README with both configuration options
• Maintains backward compatibility with existing configurations

Benefits

• ✅ Solves environment variable issues in GitHub Copilot CLI (known bug in v1.2.0)
• ✅ Better compatibility across all MCP clients
• ✅ More flexible configuration options
• ✅ No breaking changes - existing configs continue to work

Configuration Examples

Traditional (environment variables) - works in most clients:

{
  "command": "uvx",
  "args": ["minimax-mcp", "-y"],
  "env": {
    "MINIMAX_API_KEY": "your-key"
  }
}

New (CLI arguments) - works in ALL clients including Copilot CLI:

{
  "command": "uvx",
  "args": [
    "minimax-mcp",
    "-y",
    "--api-key=your-key"
  ]
}

Testing

• ✅ Tested with GitHub Copilot CLI (previously broken, now works)
• ✅ Tested with Claude Desktop (continues to work)
• ✅ Backward compatibility verified with env vars

Related Work

Similar improvements implemented in other MCP servers:

• mem0-mcp: feat: add security and reliability improvements mem0ai/mem0-mcp#26
• gitlab-mcp: feat: add CLI arguments support for configuration zereight/gitlab-mcp#291

These PRs solve the same GitHub Copilot CLI compatibility issue.