Add MCP Toplist rank badge

[chrstphe]

Hi! MCP Toplist tracks 81,686 MCP servers across the major
registries, and Appwrite MCP Server is currently ranked #474.

This PR adds a small live badge to your README showing that rank — it updates
automatically as the leaderboard changes:

Totally fine to close if you'd rather not — and if you'd like your server's
data corrected or removed from the leaderboard, just say so here or open an
issue at the site. Thanks for building Appwrite MCP Server!

[greptile-apps]

Greptile Summary

Adds a live MCP Toplist rank badge and leaderboard link near the top of the README.

Confidence Score: 5/5

The PR appears safe to merge.

The change is limited to a valid Markdown badge and external leaderboard link in the README, with no runtime, build, data, or security behavior affected.

Important Files Changed

Filename	Overview
README.md	Adds a correctly formatted Markdown badge linking to the Appwrite MCP Server’s MCP Toplist page; no actionable issues identified.

_{Reviews (1): Last reviewed commit: "Add MCP Toplist rank badge" | Re-trigger Greptile}