Automation/blog pipeline

[nora-weisser]

A daily (and manually-triggerable) GitHub Action that turns reviewed blog submissions into draft PRs.
The initial PR was opened before by Silke, I improved it.

What it does

• Reads the Form Responses sheet and publishes rows marked isReviewedandApproved but not yet isPublished
• Exports each Google Doc → sanitized HTML post, downloads the cover image (falls back to default), then opens a PR for human review
• Writes isPublished=TRUE back to the sheet so nothing is published twice — the sheet is the single source of truth

Key changes

• publish_reviewed_blogs.py — orchestrator; blog_exporter.py — Doc→post + image; blog_info_from_spreadsheet.py — sheet read/write
• HTML sanitized against an allowlist (bleach); filename slugs and YAML front matter hardened
• Robust to missing images / inaccessible Docs (skips cleanly)
• Workflow runs only on the org repo; service-account key injected from a secret and never committed

It was tested locally, it is not possible to test when it is in PR only when merged.

Pull request checklist

Please check if your PR fulfills the following requirements:

• I checked and followed the contributor guide
• I have tested my changes locally.
• I have added a screenshot from the website after I tested it locally