Function load_and_run_elf_with_stack 

pub fn load_and_run_elf_with_stack(
    elf_data: &[u8],
    name: &'static str,
    extra_args: &[&str],
    seed_caps: &[Capability],
    stack_pages: usize,
) -> Result<TaskId, &'static str>

Load an ELF64 binary with an explicit per-process user stack size.

stack_pages is expressed in 4 KiB pages and clamped to USER_STACK_MIN_PAGES..=USER_STACK_MAX_PAGES (issue #64).