Add manual release CI workflow (release.yaml)

[delthas]

Summary

Arsenal has no release workflow, unlike cloudserver, vault2, and backbeat, which each ship a workflow_dispatch release pipeline. Today arsenal releases are cut by hand via gh release create <version> --generate-notes.

This adds .github/workflows/release.yaml, triggered manually (workflow_dispatch), that:

• Reads the version from package.json (no manual tag input), so the released tag can never drift from what consumers pin (git+https://github.com/scality/arsenal#<tag>).
• Fails loudly if a release for that version already exists, guarding against accidental re-runs (softprops/action-gh-release otherwise updates an existing release silently).
• Creates the GitHub release + tag with auto-generated notes (generate_release_notes: true), targeting the dispatched commit.

Arsenal is a library (private: true, no Docker image), so the workflow reduces to the GitHub-release step only — no Docker/oras steps. Build artifacts continue to be published by the existing per-push compile job in tests.yaml. The release name is kept as the bare version (e.g. 8.5.1) to match arsenal's existing release history.

Issue: ARSN-604

[bert-e]

Hello delthas,

My role is to assist you with the merge of this
pull request. Please type @bert-e help to get information
on this process, or consult the user documentation.

Available options

name	description	privileged	authored
/after_pull_request	Wait for the given pull request id to be merged before continuing with the current one.
/bypass_author_approval	Bypass the pull request author's approval	⭐
/bypass_build_status	Bypass the build and test status	⭐
/bypass_commit_size	Bypass the check on the size of the changeset TBA	⭐
/bypass_incompatible_branch	Bypass the check on the source branch prefix	⭐
/bypass_jira_check	Bypass the Jira issue check	⭐
/bypass_peer_approval	Bypass the pull request peers' approval	⭐
/bypass_leader_approval	Bypass the pull request leaders' approval	⭐
/approve	Instruct Bert-E that the author has approved the pull request.		✍️
/create_pull_requests	Allow the creation of integration pull requests.
/create_integration_branches	Allow the creation of integration branches.
/no_octopus	Prevent Wall-E from doing any octopus merge and use multiple consecutive merge instead
/unanimity	Change review acceptance criteria from one reviewer at least to all reviewers
/wait	Instruct Bert-E not to run until further notice.

Available commands

name	description	privileged
/help	Print Bert-E's manual in the pull request.
/status	Print Bert-E's current status in the pull request TBA
/clear	Remove all comments from Bert-E from the history TBA
/retry	Re-start a fresh build TBA
/build	Re-start a fresh build TBA
/force_reset	Delete integration branches & pull requests, and restart merge process from the beginning.
/reset	Try to remove integration branches unless there are commits on them which do not appear on the source branch.

Status report is not available.

[bert-e]

Request integration branches

Waiting for integration branch creation to be requested by the user.

To request integration branches, please comment on this pull request with the following command:

/create_integration_branches

Alternatively, the /approve and /create_pull_requests commands will automatically
create the integration branches.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.54%. Comparing base (7fd2be6) to head (dd5ee2d).

Additional details and impacted files

@@               Coverage Diff                @@
##           development/8.3    #2656   +/-   ##
================================================
  Coverage            73.54%   73.54%           
================================================
  Files                  222      222           
  Lines                18188    18188           
  Branches              3786     3786           
================================================
  Hits                 13377    13377           
  Misses                4806     4806           
  Partials                 5        5           

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[francoisferrand]

As logic is added to release workflow, bugs are also added : which is esp. critical for releases, which are only used seldom and especially when we need (urgently) a release... Thus (non-trivial) release workflow should be tested, as we do for exemple in Zenko

[francoisferrand]

this only checks the release, not the tag.
if the release was previously aborted or removed, but the tag is still there, we could end up in a weird state: the tag was created -possibly on another commit- and we would now release a different commit (and possibly move the tag)

[maeldonn]

Need a test