ci: harden openapi auto-regeneration and streamline config

[gildesmarais]

This pull request updates the OpenAPI release and CI workflow to improve automation and commit handling. The most significant changes focus on how OpenAPI artifacts are managed and committed during the CI process.

OpenAPI artifact management and CI workflow improvements:

• The CI workflow now checks for changes in OpenAPI artifacts before committing and pushing. If there are no changes after regeneration, it skips the commit and push step, preventing unnecessary commits.
• The OpenAPI job in the CI workflow now explicitly sets contents: write permissions and ensures the correct git reference is checked out, which is important for release automation and branch consistency.

Release configuration:

• The .github/release-please-config.json file has been updated to only include public/openapi.yaml in the release process for OpenAPI artifacts, removing the frontend generated client files from direct release tracking.

[Copilot]

Pull request overview

This PR tightens the CI workflow around OpenAPI artifact regeneration (especially for release-please PRs) and simplifies the release-please configuration by removing generated frontend client files from the version-bump list.

Changes:

• Update the OpenAPI CI job to be able to commit/push regenerated artifacts back to the PR branch (with write permissions and full git history).
• Avoid creating empty commits by only committing when git diff --staged detects changes.
• Simplify release-please extra-files to track only public/openapi.yaml (in addition to frontend/package.json).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
.github/workflows/ci.yml	Adds write permissions and PR-branch checkout/push logic for auto-regenerating OpenAPI artifacts on release-please PRs.
.github/release-please-config.json	Removes generated TS client artifacts from release-please extra-files, leaving public/openapi.yaml as the tracked OpenAPI-related file.