Docs: consider a PowMCP SSL Certificate Check extension tutorial

## What problem would this solve?

Goose users who want to inspect a public website’s served TLS certificate and supported protocol versions need clear connection instructions and an explanation of what the result does—and does not—establish. We would like to contribute a focused tutorial for the hosted PowMCP SSL Certificate Check MCP endpoint if this fits the documentation’s scope.

## What would a good outcome look like?

A user can connect the remote endpoint, run ssl_check against a public URL, and understand hostname matching, expiry, and observed TLS versions without mistaking the result for full certificate trust-chain validation, revocation checks, cipher-suite analysis, or coverage of every load-balanced node.

## Possible approaches

A documentation-only extension tutorial using the existing HTTP setup components. No Goose core changes are proposed. Guest access has usage limits and requires no credential; optional account linking should only be described after it is tested in Goose. Goose end-to-end testing has not been completed yet. We will wait for maintainer scope/verification guidance and a Ready issue before implementing or opening a PR.

## Additional context

- Product: https://powmcp.com/apps/ssl-certificate-check/
- Endpoint: https://powmcp.com/ssl-certificate-check/mcp
- Maintainer: PowMCP, a product of Frostwave Labs Inc.; support@powmcp.com
- Future contribution fork: https://github.com/powmcp/goose
- Hosted proprietary service; this is not an open-source server implementation submission.

This is an agent-assisted request submitted with the product owner’s explicit authorization. We recognize the contribution guide asks contributors to write their issues personally; if direct owner participation is required for this documentation proposal, please let us know before we proceed.

- [x] Searched existing issues for powmcp.com; no duplicate found.