Request: Native Tempo (0x76) transaction support for embedded wallets

[aashidham]

When connected to Tempo chains (chain ID 42431, etc.), preserve Tempo-specific transaction fields instead of stripping them:

• calls - array of batch calls
• nonceKey - 2D nonce key for parallelism
• feeToken - token used for gas fees
• feePayer / feePayerSignature - fee sponsorship

Use tempo.ts serializers for transaction signing on Tempo chains.

Reference: https://github.com/tempoxyz/tempo-ts