feat(userspace): shell runs programs (ls, cat) via spawn w/ terminal+storage+args page; ext4 holes read as zeros; storage re-attach same buffer

crates/init/src/launch.rs

@@ -153,6 +153,6 @@ fn hand_over_console(log: CapSlot) {
 pub(crate) fn start(program: &LoadedProcess, console: Option<CapSlot>) {
     let log = libkos::start::log()
         .and_then(|l| syscall::delegate(l, program.process_cap, perms(&[Permission::Execute])));
-    let arg = types::start_arg::encode(console, log);
+    let arg = types::start_arg::StartArg { console, log, ..Default::default() }.encode();
     syscall::spawn_thread_in(program.process_cap, program.entry_point, USER_STACK_TOP, arg);
 }