Action provider proposal: Ophis (CoW Protocol) ERC-20 swaps

### Summary

`WISHLIST.md` lists DeFi swap integrations — I've built an AgentKit action provider for **Ophis** (a CoW Protocol fork) that fits: a `swap` action giving agents intent-based, MEV-protected ERC-20 swaps. Already published and working:

- npm: [`@ophis/agentkit-ophis`](https://www.npmjs.com/package/@ophis/agentkit-ophis)
- source: https://github.com/ophis-fi/ophis/tree/main/packages/agentkit-ophis
- built on `@coinbase/agentkit` (`ActionProvider` + `@CreateAction`, zod 3)

### Proposal

I'd like to vendor it into `typescript/agentkit/src/action-providers/ophis/` (mirroring an existing swap provider), with the README block, a changeset, tests, and an `examples/` chatbot demonstrating a real swap — matching the shape of the dTelecom provider PR (#982).

Before I open the PR — is this something you'd accept? Happy to follow CONTRIBUTING (signed commits, the PR template with a real swap transcript). Thanks!