Add Gravity Swarm MCP to Tools section

MCP server for an agent reputation network using Nostr BIP-340 signing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -461,6 +461,7 @@ Websites with lists of relays and their performance/health:
 - [gittr-helper-tools](https://github.com/arbadacarbaYK/gittr-helper-tools)![stars](https://img.shields.io/github/stars/arbadacarbaYK/gittr-helper-tools.svg?style=social) - Production code snippets from gittr.space: file fetching, URL normalization, GRASP detection, NIP-46 signer, NIP-25 stars, NIP-51 following, markdown media handling, and NIP-C0 code snippets.
 - [granary](https://github.com/snarfed/granary)![stars](https://img.shields.io/github/stars/snarfed/granary.svg?style=social) - Convert nostr content into atom, html, rss, json, indieweb feed, mastodon, microformats2, activitystreams, activitypub/fediverse, jsonfeed, and bluesky's atproto all with web and rest-api. 
   - [granary.io](https://granary.io/) - live instance 
+- [Gravity Swarm MCP](https://github.com/antoinedelorme/gravity-swarm-mcp)![stars](https://img.shields.io/github/stars/antoinedelorme/gravity-swarm-mcp.svg?style=social) - MCP server for an agent reputation network using Nostr BIP-340 signing. AI agents enlist, compute deterministic tasks, answer questions, submit proofs, and earn ELO — all with Nostr-compatible identities.
 - [heyxynip5](https://github.com/bennyhodl/hexynip5)![stars](https://img.shields.io/github/stars/bennyhodl/hexynip5?style=social) - A CLI helper for converting nostr npub/nsec to their hex format for NIP-05 verification.
 - [homebrew-nostr](https://github.com/nostorg/homebrew-nostr)![stars](https://img.shields.io/github/stars/nostorg/homebrew-nostr?style=social) - Homebrew tap for Nostr software.
 - [hostr](https://github.com/studiokaiji/nostr-webhost) - nostr-webhost is a tool for hosting SPA on nostr