Function program_full_tower 

pub fn program_full_tower<const K: usize, P: RowProgram<K> + ?Sized>(
    prog: &P,
    row: usize,
) -> Result<Box<Tower4<K>>, String>

Derive every channel (v, g, h, t3, t4) in one pass from a RowProgram at the full dense Tower4 scalar.

The result is boxed so the return slot itself remains bounded independently of K. Dense towers above the canonical storage budget are rejected before the program is touched; consumers at those widths must request only the channels they need through program_row_kernel, program_third_contracted, and program_fourth_contracted.