Function apply_internal_tx_update 

pub fn apply_internal_tx_update<D: Database, B: Burner, F, G>(
    data: &[u8],
    state: &mut ArbosState<D, B>,
    ctx: &InternalTxContext,
    transfer_fn: F,
    balance_of: G,
) -> Result<(), String>
where
    F: FnMut(Address, Address, U256) -> Result<(), ()>,
    G: FnMut(Address) -> U256,

Apply an internal transaction update to ArbOS state.

Dispatches on the 4-byte method selector to handle:

• StartBlock: records L1 block hashes, reaps expired retryables, updates L2 pricing, and checks for ArbOS upgrades.
• BatchPostingReport (v1 and v2): updates L1 pricing based on batch poster spending.