docs: add @getpitstop/sdk to extensions

[kriss39]

Adds @getpitstop/sdk to the extensions list. It sets up and watches spending limits for agents that pay MPP services from a Tempo wallet:

• A passkey owns the wallet, and the agent gets an Account Keychain access key with a periodic limit, one token, an expiry and, optionally, TIP-1011 recipient scopes so it can only pay the listed services. agentAccount signs with that key and plugs into mppx/client's tempo method.
• It funds the wallet from Base, Solana, Ethereum, Arbitrum and other chains through LI.FI (USDC.e, pathUSD, USDT0), and can refill it automatically from a small home wallet.
• @getpitstop/mcp (npx -y @getpitstop/mcp) lets Claude, Cursor or Codex check the key's remaining limit and balance and request fuel. It has no tool that raises a limit.

Published on npm, MIT. Running on Tempo mainnet: an agent paid Nansen and Codex per call through its access key, and the call over the limit was refused with SpendingLimitExceeded. Web app: https://fuel.pitstopgas.workers.dev

[vercel]

@kriss39 is attempting to deploy a commit to the Tempo Team on Vercel.

A member of the Team first needs to authorize it.