Update metricshub/workflows to v7

[NassimBtk]

GitHub runners now ship Maven 3.10.0 (image ubuntu24/20261004 and later). This PR aligns the project with MetricsHub/jflat and MetricsHub/simple-http-java.

What changed

• metricshub/workflows v4 → v7 (build, deploy and release). The inputs are unchanged.
  • v7 declares https://central.sonatype.com as an origin of server central (Declare Central as an origin of server central for Maven 3.10 workflows#36).
  • Maven 3.10 needs this to send the publishing token to Central. Without it, snapshot deploys fail with HTTP 401 ("Not using credentials of server 'central' for repository https://central.sonatype.com").
• The site is already on Doxia 2, so it is not changed.
• oss-parent is already 5.

Validation

• jflat and simple-http-java use the same v7 workflows. Their deploys on Maven 3.10.0 end in BUILD SUCCESS, and new snapshots are published on Central (the origin step passes).
• This PR's CI runs the build (and the site) on the runner's Maven.
• After the merge, check the first Maven Deploy run on main:
  • no "Not using credentials of server 'central'" warning in the deploy step;
  • central-publishing:publish ends in BUILD SUCCESS;
  • a new snapshot timestamp appears on Central.

🤖 Generated with Claude Code

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-08T16:46:49.716467Z	190f57d	New commits

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 4e69ef9313

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Update the release instructions for Central Portal

With the v7 release workflow, releases use Central Publishing with server ID central, but README.md:55-62 still directs maintainers to the legacy s01.oss.sonatype.org repository, server ID ossrh, and Nexus staging console. Because autoRelease remains false, anyone following those instructions after a successful release will look in the wrong console and cannot publish the pending deployment; update the release documentation alongside this workflow migration.

AGENTS.md reference: AGENTS.md:L31-L35

Useful? React with 👍 / 👎.

[bertysentry]

Done in 190f57d: the release instructions now point at the Central Portal (server id central, publish the pending deployment at https://central.sonatype.com/publishing/deployments since autoRelease is false).