Function initialize_arbos_state 

pub fn initialize_arbos_state<D: Database>(
    state: &mut State<D>,
    init_msg: &ParsedInitMessage,
    chain_id: u64,
    target_arbos_version: u64,
    chain_owner: Address,
) -> Result<(), String>

Initialize ArbOS state in a freshly created database.

This sets up:

• ArbOS version (set to 1, then upgrade to target version)
• All precompile accounts with [0xFE] invalid code marker
• L1 pricing state (initial base fee, batch poster table)
• L2 pricing state (base fee, gas pool, speed limit)
• Retryable state, address table, merkle accumulator, blockhashes
• Chain owner and chain config

The init_msg comes from parsing the L1 Initialize message (Kind=11).