fix(relayer): match wallet-webapp FeeOptions request shape

[taylanpince]

What / Why

We observed Polygon Relayer/FeeOptions failures for undeployed v3 wallets when the client requests fee options using the guest module as the simulation target.

wallet-webapp-v3 successfully requests fee options for the same wallet by calling:

• wallet = <walletAddress>
• to = <walletAddress>
• data = Payload.encode(calls, self=<walletAddress>) (raw 0x03… bundle)

That request shape returns fee options reliably on Polygon.

This PR updates RpcRelayer.feeOptions to match the wallet-webapp-v3 request shape:

• force to = wallet
• encode payload with self = wallet

This avoids guest-module simulation pitfalls while still representing the same underlying meta-transaction bundle.

Notes

• This was validated end-to-end in our ecosystem-wallet CLI on Polygon: fee options returned and a send-native --broadcast succeeded for an undeployed wallet.

Risk

Low: this only affects the request shape for the FeeOptions call; the returned fee options and the subsequent SendMetaTxn flow remain unchanged.