Add Liquid Gas Sponsor (x402-paid ERC-4337 paymaster on Base) + Liquid Agent x402 examples

[LeftyChris13]

Two additions, both live on Base mainnet:

• Ecosystem → Liquid Gas Sponsor — https://api.liquidagent.ai/v1/gas. An ERC-4337 paymaster that agents pay per operation in USDC over x402 (from $0.03), so a wallet holding USDC and no ETH can transact. One endpoint serves smart-wallet SDKs (standard ERC-7677 JSON-RPC; the 402 rides inside the JSON-RPC error) and plain EOAs (EIP-7702 delegation: {sender, calls} → 402 quote → pay → sign → submit). Fees settle through public facilitators (PayAI, Heurist). Public stats: https://api.liquidagent.ai/v1/gas/stats. Listed on x402scan.
• Example Apps → Liquid Agent x402 examples — https://github.com/LiquidAgent/liquidagentx402: open examples (JS/Python/curl) for the tokenized-stock index, including examples/gasless.js where a zero-ETH wallet pays the sponsor in USDC and buys the index end to end.

Primary sources: OpenAPI https://api.liquidagent.ai/openapi.json · x402 resource catalog https://api.liquidagent.ai/.well-known/x402-resources