fix(release): allow an empty commit when cutting the ORB stable Release PR

[JSONbored]

Summary

• Follow-up to feat(release): automate the ORB stable-release channel with a standing Release PR #5063. Confirmed live on the very first real orb-stable-release-pr run: orb-manifest.json already declared "0.4.0", and buildOrbStableReleaseReport's inferred next version was also 0.4.0 (the common case right after a maintainer hand-bumps the manifest ahead of landing the commits that warrant it) -- so writing the "proposed" version produced a byte-identical file, git add staged nothing, and git commit failed outright before the push/PR-create steps ever ran.
• Fix: git commit --allow-empty -- the branch/PR is the reviewable release marker regardless of whether the manifest content actually changes.
• Verified the fix live: re-dispatched orb-stable-release-pr.yml against this fix branch directly (workflow_dispatch with --ref) and it succeeded, correctly opening chore(release): cut orb-v0.4.0 #5066 (chore(release): cut orb-v0.4.0) with the full commit list since orb-v0.3.0 in the body.

Maintainer PR (JSONbored) -- no linked issue per the repo's maintainer exception.

Scope

• The PR title follows type(scope): short summary Conventional Commit format.
• This PR is focused (one workflow file, one line changed plus a comment).
• This follows CONTRIBUTING.md and does not reintroduce GitHub Pages, VitePress, site/, or CNAME.
• Maintainer PR -- no linked issue required.

Validation

• git diff --check
• npm run actionlint
• npm run typecheck
• Live-verified against the real repo: re-ran the fixed workflow via workflow_dispatch --ref on this branch, confirmed it now succeeds and opens a correct Release PR (chore(release): cut orb-v0.4.0 #5066).
• npm audit --audit-level=moderate -- 0 vulnerabilities (no dependency changes).

Safety

• No secrets, wallet details, hotkeys, coldkeys, user PATs, private keys, raw trust scores, private rankings, or private maintainer evidence are exposed.
• Auth, cookie, CORS, GitHub App, Cloudflare, or session changes include negative-path tests. (N/A -- CI workflow only.)
• Public docs/changelogs are updated where needed; changelogs are only edited for release-prep PRs. (N/A.)

Notes

• Backend/CI-infra-only one-line fix; no UI Evidence section.

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.13%. Comparing base (3213313) to head (f4363c5).
⚠️ Report is 3 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5067   +/-   ##
=======================================
  Coverage   94.13%   94.13%           
=======================================
  Files         465      465           
  Lines       39554    39554           
  Branches    14433    14433           
=======================================
  Hits        37235    37235           
  Misses       1664     1664           
  Partials      655      655           

Flag	Coverage Δ
shard-1	46.50% <ø> (ø)
shard-2	33.56% <ø> (ø)
shard-3	31.33% <ø> (ø)
shard-4	32.68% <ø> (ø)
shard-5	33.43% <ø> (ø)
shard-6	44.94% <ø> (ø)

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