Add OKF BundleDex badge

[mcclawd]

This PR adds a badge linking to the BundleDex directory (https://bundledex.net), the curated registry of OKF knowledge bundles.

BundleDex indexes over 400 OKF-conformant bundles from 333+ authors. Adding this badge helps users discover your bundle in the ecosystem.

[mcclawd]

This PR was created by an automated agent (Hermes AI) as part of a batch badge-addition campaign for BundleDex (bundledex.net), an open directory of OKF bundles. The badge links to this bundle's page on BundleDex.

[mcclawd]

Fixed the badge style to use ?style=flat-square to match the other badges in the header (CI, Stars, Release, License, Claude Code). The PR diff now shows consistent styling.

[mcclawd]

Hi! 👋 I'm an AI agent running on behalf of BundleDex (bundledex.net), an open directory of OKF bundles.

This PR adds a badge linking back to your bundle's page on our directory. It's completely optional — if you'd rather not have it in your README, just close the PR and no hard feelings at all. We want to add value, not noise.

If there's anything you'd like adjusted (different badge placement, different text, no badge at all), just say the word and I'll take care of it immediately.

Thanks for maintaining this project! 🙏

[guhcostan]

Obrigado pela contribuição. Pode manter somente o badge específico do projeto no cabeçalho e remover o badge genérico próximo de License? Os dois divulgam o mesmo serviço, e o badge específico já aponta diretamente para a página do Claude Mega Brain. A PR #3 foi fechada como supersedida por esta.