Add blindoracle-sdk (Grok Bot kit) to plugins and MCP servers

[craigmbrown]

What kind of change is this?

• New catalog entry
• Fix a broken/outdated entry
• Other (README, CONTRIBUTING, infra, etc.)

Checklist (for new entries)

• The linked repo resolves and is not empty/archived.
• It's genuinely about Grok Bot (xAI + Cursor's cloud-computer product), not Grok Build or an unrelated
  same-named bot.
• It's not already listed anywhere in this README.
• The entry follows the exact format: - [name](repo-url) by [author](author-url) — description. **[tag]**
• It's placed alphabetically within the correct category.

Anything else maintainers should know?