Fix /app/resta.s so that the assembled and linked executable prints exactly 5 - 3 = 2 followed by a newline…

Fix /app/resta.s so that the assembled and linked executable prints exactly 5 - 3 = 2 followed by a newline…: a task in rts-1k-rootless-apptainer: RTS-1K: offline rootless Apptainer release (Harbor dataset). What the agent is asked, how it is graded, what it runs in, and its files.