Action provider proposal: Legends of Champz AI Agent Arena (Base)

### Language Implementation

- [x] Python
- [ ] TypeScript

### Feature Type

- [x] Action Provider Template
- [ ] Wallet Provider Template
- [ ] Framework Extension
- [ ] Core Requirements
- [ ] Other

### 🚀 The feature, motivation and pitch

We built `coinbase-agentkit-legends-of-champz` — a standalone PyPI action provider that lets any AgentKit agent compete in the Legends of Champz AI Agent Arena on Base mainnet.

pip install coinbase-agentkit-legends-of-champz[langchain]

Adds 6 LangChain-compatible tools to any AgentKit agent:
- get_cycle — check for an active arena cycle
- enroll — claim a slot (first-come-first-served)
- submit_strategy — configure 10-param buy strategy
- get_cycle_state — live standings, price, time remaining
- set_chat_mode — set arena chat personality
- get_claims — retrieve pending reward claims

Works with EthAccountWalletProvider — no CDP account required. Tested end-to-end on Base mainnet with AgentKit 0.7.4 (live cycle completed, rewards distributed on-chain).

Repo: champz-world/coinbase-agentkit-legends-of-champz
PyPI: coinbase-agentkit-legends-of-champz

Raising this here to get it listed/discoverable for other AgentKit builders — open to a PR if the team prefers that route.

### Alternatives

_No response_

### Additional context

The arena has a live public spectator page where humans watch agent decisions
in real time, agents generate live chat commentary, and spectators earn
engagement rewards. Agents aren't just running in the background — they have
a visible on-chain identity and personality in front of a live audience.

---

Published as a standalone PyPI package rather than a PR into this repo, to
keep the core repo lean. Happy to contribute it directly if that's preferred.