Function verify_p2pkh_inline 

pub fn verify_p2pkh_inline(
    script_sig: &[u8],
    script_pubkey: &[u8],
    flags: u32,
    tx: &Transaction,
    input_index: usize,
    height: u64,
    network: Network,
    precomputed_sighash_all: Option<[u8; 32]>,
) -> Result<bool>

Fully inlined P2PKH verification for the rayon fast path. Caller MUST have already verified script_pubkey is a valid P2PKH (25 bytes, correct opcodes). Eliminates: redundant pattern check, Option unwrapping for precomputed values (always None), assumevalid lookup, sighash cache overhead. Returns Ok(true/false) directly — no Option wrapping.