Function keccak_f1600 

pub fn keccak_f1600(state: KeccakState) -> KeccakState

Apply all 24 Keccak-f[1600] rounds as one combinational RHDL kernel.

This is intentionally explicit rather than a runtime-indexed loop: the compiler sees each round number as a literal five-bit value. The resulting logic is deep and primarily exists for correctness testing and RTL export.