[Docs]: Add documentation for using mcp-cli with MCP Gateway

[crivetimihai]

📚 Documentation Issue Summary

Please add documentation for using mcp-cli as a client with MCP Gateway.

mcp-cli is a Python-based command-line interface for interacting with MCP-compliant servers. Adding it to the docs will help users test, debug, or script against MCP Gateway instances without needing to use a browser-based tool. It's especially useful for automation, CI, or quick terminal-driven interaction.

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📍 Location of the Problem

Suggested new page: docs/docs/using/clients/mcp-cli.md
Also link it from the .pages file.

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✏️ Type of Issue

• Typo or formatting issue
• Outdated or incorrect information
• Missing explanation or example
• Unclear instructions
• Other (explain below)

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🧩 Additional Notes (optional)

Include usage for Bearer token auth and support for mcpgateway-wrapper flows (e.g. using a local wrapper for dev testing).

[manavgup]

@crivetimihai, my plan to address this is:

1. Create a new documentation page at docs/docs/using/clients/mcp-cli.md that:

   • Introduces mcp-cli as a Python CLI tool for interacting with MCP Gateway.
   • Explains how to use it with Bearer token authentication, referencing the MCP_AUTH_TOKEN environment variable.
   • Describes how to use it with mcpgateway-wrapper for local development/testing, including setting MCP_SERVER_CATALOG_URLS and running the wrapper.
   • Provides example commands and configuration snippets based on the README content and typical usage patterns.
   • Mentions the stdio transport and its role in enabling clients without SSE support.

2. Update the docs/docs/using/.pages file to add a link to this new mcp-cli documentation page for discoverability.

3. Verify the instructions by testing mcp-cli usage with MCP Gateway and mcpgateway-wrapper locally if feasible.

let me know your thoughts and I can start working on it.

[crivetimihai]

Sounds good, thanks! You can also close #19 as well, similar ticket, just cover it in the same documentation.