feat: support per-call value transfers in batch transactions

[gakonst]

Summary

The Tempo transaction spec defines per-call value transfers in batch transactions:

pub struct Call {
    to: TxKind,
    value: U256,  // ← Value per call is spec'd
    input: Bytes
}

However, the node currently rejects batch transactions with non-zero call values:

error code -32603: Revm error: value transfer in Tempo Transaction not allowed

Context

• Spec reference: spec-tempo-transaction.mdx
• Foundry PR: feat(cast): add batch-send and batch-mktx commands for Tempo native batching tempo-foundry#218 implements cast batch-send with value support, but tests are disabled pending node support
• Test command: cast batch-send --call "0x...:0.0001ether" --call "0x...::fn()"

Expected Behavior

Batch transactions should allow per-call value transfers, enabling atomic operations like:

• ETH transfers + contract calls in one tx
• Multi-recipient payments
• DEX operations with ETH value

Acceptance Criteria

• Node accepts batch transactions with non-zero value in Call structs
• Gas estimation accounts for value transfers correctly
• Re-enable CAST BATCH-SEND WITH VALUE test in tempo-foundry CI