Add BlackVault — Proxy gateway for AI API keys

[venkat22022202]

Summary

• Adds BlackVault to the Advanced Agents section in the README
• BlackVault is an open-source proxy gateway for AI API keys — agents never see the real key. Generate proxy tokens, and BlackVault injects the real key server-side and forwards requests to OpenAI, Anthropic, Google AI, and Nebius AI with full SSE streaming. Kill a session for instant access revocation.
• Built with Next.js, tRPC, Neon Postgres, and Upstash Redis
• Licensed under MIT

Closes #134

Nebius AI support was added as requested by @shivaylamba.

Tech Stack

• Next.js + tRPC — full-stack framework and type-safe API layer
• Neon Postgres — serverless database for vault storage
• Upstash Redis — rate limiting and session caching
• SSE streaming — real-time proxy forwarding for OpenAI, Anthropic, Google AI, and Nebius AI

Test plan

• Verify the README entry renders correctly and links to the correct repository
• Confirm the project count in the Advanced Agents section is updated to 15
• Check that the entry format matches existing entries in the list

🤖 Generated with Claude Code

[shivaylamba]

Add an example showing Nebius Token Factory