fix(ci): Release workflow failed on every tag whose release already existed

[Thomasbehan]

Run 30226581630 failed on the v5.0.0 tag:

unknown flag: --generate-notes
Usage:  gh release edit <tag>

Root cause

gh release edit does not support --generate-notes — only gh release create does. So this branch of the workflow could never succeed:

if gh release view "$TAG" >/dev/null 2>&1; then
  gh release edit "$TAG" --generate-notes   # always exits 1
else
  gh release create "$TAG" --generate-notes --title "LesNet $TAG"
fi

It has been latent since the workflow was written and only passed when the release did not already exist, i.e. when the create path ran. Pushing v5.0.0 — whose release was created beforehand so the model assets could be attached — took the broken branch.

Fix

An existing release is now left alone. This is more than crash-avoidance: had edit --generate-notes worked, it would have overwritten the curated release notes (metrics tables, limitations, usage) with an autogenerated commit changelog.

Verified locally: YAML parses, shell logic passes bash -n, and gh release edit --help confirms the flag does not exist.

Test plan

• python -c "yaml.safe_load(...)" parses the workflow
• bash -n on the extracted script
• Confirmed against gh release edit --help
• Next v* tag push exercises it for real