feat(ipc): saved replies: SaveReply/ReplySaved (8 per thread, released on thread death, unforgeable); terminal READ saved until Enter (line.rs editor, reader queue), now pinged

crates/kernel/src/syscall/mod.rs

@@ -138,6 +138,14 @@ impl<P: Platform> Kernel<P> {
             Syscall::ReplyRecv { endpoint, message } => {
                 self.reply_recv(tid, pid, endpoint, message)
             }
+            Syscall::SaveReply => complete(
+                self.save_reply(tid)
+                    .map(|r| SyscallResult::Value(usize::from(r.value()))),
+            ),
+            Syscall::ReplySaved { reply, message } => complete(
+                self.reply_saved(tid, pid, reply, message)
+                    .map(|()| SyscallResult::Ok),
+            ),
             Syscall::CreateNotification => {
                 complete(self.create_notification_cap(pid).map(SyscallResult::Slot))
             }