v0.16.19 added the swapfile step but failed on the first run with
`fallocate: fallocate failed: Text file busy` — the ubuntu-24.04-arm
runner ships with a pre-mounted /swapfile (4 GB), so the new
fallocate call hit an in-use inode and exited non-zero before the
linker could benefit.

Robust pattern (matches what pierotofy/set-swap-space@master does
internally):

  sudo swapoff -a || true
  sudo rm -f /swapfile
  sudo dd if=/dev/zero of=/swapfile bs=1M count=8192 status=progress
  sudo chmod 600 /swapfile
  sudo mkswap /swapfile
  sudo swapon /swapfile

swapoff first releases the in-use mapping; rm clears the file
(fallocate-on-swap-flagged-inode would still fail even post-swapoff
on some kernels); dd unconditionally writes 8 GB of zeros which
every fs accepts. `|| true` on swapoff makes the step idempotent —
re-runs after partial failure don't trip on "no swap mounted."

Also added `swapon --show` for log diagnosis if the runner's swap
ever silently regresses again.

No code changes vs. v0.16.19. 8 standard version-string bumps for
the meta gates, plus the workflow patch.