Function init_precompile_gas_pure 

pub fn init_precompile_gas_pure(
    gas_used: &mut u64,
    ctx: &ArbPrecompileCtx,
    input_len: usize,
)

Initialize gas tracking for a pure precompile method: like init_precompile_gas but skips the OpenArbosState SLOAD, matching the reference framework’s pure-method path which does not open ArbOS state.