docs: add Voidly Pay — agent-to-agent payment rail (x402, USDC)

[EmperorMew]

Adding Voidly Pay to the directory. It's an MCP server that exposes an agent-to-agent payment rail — AI agents charge each other in USDC-backed credits over HTTP 402 (x402).

• npm: @voidly/pay-mcp — 28 tools (wallet, transfer, escrow, hire, marketplace, x402 quote/verify, universal proxy, capability listing, faucet, trust scoring)
• Universal proxy: /v1/pay/proxy?u=<url>&to=<did>&price=<usdc> — paywalls any public HTTPS URL with one query param. No SDK install required on the URL owner's side.
• USDC-backed: Stage 2 vault on Base mainnet, source-verified on Sourcify. Public reserves dashboard at https://voidly.ai/pay/proof
• Repo: https://github.com/voidly-ai/voidly-pay
• Manifest: https://api.voidly.ai/v1/pay/manifest.json

Thanks for maintaining mcp.so 🙏

[BossChaos]

Code Review

PR: docs: add Voidly Pay — agent-to-agent payment rail (x402, USDC) by @EmperorMew

• ✅ Feature addition

Wallet: 0xdaE5d307339074A24F579dB48e7c639359D94904

Code review