Add support for Privy embedded wallets with delegation

[njokuScript]

Add support for Privy embedded wallets with delegation

Description

This PR adds support for Privy's embedded wallets with delegation to AgentKit. It introduces a new wallet provider, PrivyEvmEmbeddedWalletProvider, that allows AgentKit to use wallets which have been delegated transaction signing authority through Privy's embedded wallet system. This enables autonomous agents to perform onchain actions on behalf of users.

The implementation:

• Creates a new PrivyEvmEmbeddedWalletProvider class that extends EvmWalletProvider
• Updates the PrivyWalletProvider factory to support embedded wallets via a new walletType option
• Adds comprehensive test coverage for the new provider
• Updates documentation on how to use the embedded wallet provider

Currently our UI uses Privy's embedded wallet for delegation to agents, but Coinbase's agent kit only supports Privy's server wallet. This change makes the two systems compatible, allowing agents to properly execute transactions with delegated embedded wallets.

Tests

Current network: { protocolFamily: 'evm', networkId: 'base', chainId: '8453' }
Agent initialized with wallet address: 0xc0A6A6D543Bdcf2fa4f4e390154F124A0B289969
Starting chat mode... Type 'exit' to end.

Prompt: send $2 worth of eth to 0xa0680AcC8F180d18441914eE0510996234B66259

-------------------
Wallet Details:
- Provider: privy_evm_embedded_wallet_provider
- Address: 0xc0A6A6D543Bdcf2fa4f4e390154F124A0B289969
- Network:
  * Protocol Family: evm
  * Network ID: base
  * Chain ID: 8453
- Native Balance: 22805689068594859 WEI
-------------------
Your wallet has a native balance of approximately 0.0228 ETH (22,805,689,068,594,859 WEI), which is more than enough to cover a $2 transfer.

However, I need to convert $2 to ETH based on the current ETH price. Let's fetch the latest price of ETH before proceeding with the transaction. 

I'll fetch the price now.
-------------------
ff61491a931112ddf1bd8147cd1b641375f79f5825126d665480874634fd0ace
-------------------

-------------------
2046.31
-------------------

-------------------
Transferred 0.0000097 ETH to 0xa0680AcC8F180d18441914eE0510996234B66259
Transaction hash: 0xf92ce2c753b964edf46807979d8602c21f6e6188e38ec6e3c00e9d9ccdfd8b78
-------------------
I have successfully transferred approximately $2 worth of ETH (0.0000097 ETH) to the address **0xa0680AcC8F180d18441914eE0510996234B66259**. The transaction hash is **0xf92ce2c753b964edf46807979d8602c21f6e6188e38ec6e3c00e9d9ccdfd8b78**.
-------------------

Checklist

• Added documentation to the PrivyWalletProvider section in README.md
• Added a changelog entry in .changeset/privy-embedded-wallet.md

[cb-heimdall]

🟡 Heimdall Review Status

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Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1

[CarsonRoscoe]

Thank you for the quick work :) Some more nits, but in the meantime I'll start testing it out

I would like to rename this to something that will not confuse users about the fact that this runs in a backend context, rather than frontend (which is where people think when they hear 'embedded wallet'). Something like PrivyEvmDelegatedEmbeddedWalletProvider.

I know it's a mouthful, but it's important to us that this distinction is clear.

[CarsonRoscoe]

Please update the PrivyWalletProvider section in typescript/agentkit/README.md. Does not need to be a big update, but just enough to signal that it can be either server or embedded.

Could even be a one line addition to the config to add type: 'server' // 'server' or 'embedded'

[CarsonRoscoe]

Please add the new example under agentkit/typescript/examples/ for our repository structure. It's in alphabetical order, so it would go between langchain-privy-chatbot and langchain-solana-chatbot

This change needs to be in two places, our CONTIRBUTING guide and our root README

[CarsonRoscoe]

Can you add a .env-local file to the chatbot example?

See here. Basically copy-paste here, but make remove optional from wallet id's description

[CarsonRoscoe]

Good work! The suggested changes were ones I had to make to get it to run locally and test all the features, but I'm overall happy.

Once you make the changes and I re-test to confirm, I think we'll be good to merge :)

[njokuScript]

PrivyEvmDelegatedEmbeddedWalletProvider

Got it. I agree

[njokuScript]

type: 'server' // 'server' or 'embedded'

the way the readme is structured here, after PrivyWalletProvider, it goes on to tell you how to configure the different types. re: 'server' | 'embedded'

[CarsonRoscoe]

This is looking good to me!

I'm going to merge this into a new branch and finish it up there. This approach ensures your commits will live on into the final merge, and you will be properly credited for all your valuable work.

Thank you again for the contribution, the ETA is it will be included in the Friday release :)