Add detailed documentation for Apidog MCP Client, highlighting its features and capabilities.

Motivation and Context

This PR adds Apidog to the list of MCP Clients. Apidog now features a built-in MCP Client designed specifically for debugging and testing MCP Servers. It supports both STDIO and HTTP transport modes, along with comprehensive support for Tools, Prompts, and Resources, making it a valuable tool for the MCP developer community.

How Has This Been Tested?

The Apidog MCP client is a live production feature currently available at https://apidog.com/. The tool has been rigorously tested and is currently used by a large base of real users. Detailed usage instructions and documentation can be found here: https://docs.apidog.com/mcp-client-1930835m0.

Breaking Changes

None. This merge is only to add a new MCP client to the list.

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 Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

1. Client Name: Apidog MCP Client
2. Homepage: https://apidog.com/
3. Description:
   Apidog provides a visual interface for interacting with MCP servers, distinct from CLI-based clients. It simplifies the debugging process by offering:

• Visual Inspection: View raw JSON-RPC messages and envelopes for detailed debugging.
• Form-Based Inputs: Auto-generated forms for Tool arguments based on schema.
• Connection Troubleshooting: Detailed logs for connection events and errors.
• Dual Mode Support: Seamlessly switch between testing local servers (STDIO) and remote deployments (HTTP).

4. Documentation: https://docs.apidog.com/mcp-client-1930835m0
5. Supported Capabilities: Tools, Prompts, Resources