feat(ecosystem): Add Teardrop - streaming agent API with native x402 settlement on Base

[HASAVAGE]

Summary

Adds Teardrop to the x402 ecosystem under the Services/Endpoints category.

Teardrop is a live streaming agent API at teardrop.dev that uses x402
as its primary per-request payment rail. x402 is not middleware, payment
verification and settlement are woven directly into the SSE execution loop:
verify before the stream opens, settle on-chain after it closes.

What Teardrop does

Sign in with an Ethereum wallet (SIWE), send a message to /agent/run, and receive
a live SSE stream of agent reasoning, tool calls, and structured UI gated by a
402 Payment Required response if no payment header is present. The stream includes a
BILLING_SETTLEMENT event with the on-chain tx_hash once settled.

Protocol stack:

• AG-UI — streaming agent events (SSE)
• A2A — agent discoverability (/.well-known/agent-card.json)
• MCP — tool serving (16 native tools)
• x402 — per-request USDC settlement on Base

x402 implementation details:

• Network: eip155:8453 (Base mainnet), eip155:84532 (Base Sepolia)
• Scheme: exact
• Token: USDC
• Facilitator: https://x402.org/facilitator
• Auth gate: SIWE (wallet = identity + payment method in one)
• Pricing: usage-based (tokens_in, tokens_out, tool_calls), dynamic via DB pricing rules

Links

• Dashboard: https://teardrop.dev
• Swagger / API docs: https://teardrop.dev/docs OR https://teardrop.onrender.com/docs
• Agent card (A2A): https://teardrop.onrender.com/.well-known/agent-card.json

Files added

• typescript/site/app/ecosystem/partners-data/teardrop/metadata.json
• typescript/site/public/logos/teardrop.png

Checklist

• Working mainnet integration (Base, eip155:8453)
• API documentation available at teardrop.dev/docs
• 99%+ uptime target (deployed on Render + Neon Postgres)
• x402 exact scheme, USDC on Base
• Settlement tx_hash returned to client in SSE stream

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