[Feat]: Add Agent Identity Protocol (AIP) to partners list

### Is your feature request related to a problem? Please describe.

Request to add Agent Identity Protocol (AIP) to `docs/partners.md`.

AIP is an open protocol for verifiable, delegable AI agent identity across MCP and A2A. Spec plus implementations in Rust, Python, and TypeScript, published as `agent-identity-protocol` on PyPI and submitted as an IETF Internet-Draft (draft-prakash-aip-00). The Python SDK ships an `aip_a2a` module that binds AIP identities and delegation chains to A2A agents.

Site: https://sunilprakash.com/aip/
Repo: https://github.com/sunilp/aip

### Describe the solution you'd like

One line added to the partners list, PR attached.

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct