Document Blueprints: Move to the Library section and per-user access for v19

[lauraneto]

📋 Description

In Umbraco 19, Document Blueprints move from the Settings section to the Library section, and access to them is set with a Document Blueprint start node on User Groups and Users. This updates the v19 docs to match:

• Document Blueprints article: steps now start from the Library section, creating from a document includes choosing a destination folder, and a new section explains access and the default groups that have it. It also links to the new Content Type Filter method.
• Sections: Document Blueprints are listed under Library instead of Settings.
• Users: start nodes, the Editors defaults, and the Assign access description now include Document Blueprints.
• Content Type Filters: adds FilterAllowedForBlueprintsAsync.
• Breaking Changes Overview: adds the Umbraco 19 entry, covering how access is granted during the upgrade.
• Screenshots: five new -19 screenshots taken on v19, with the replaced images removed from the 19 folder only.

This PR was written with AI assistance and reviewed by me.

📎 Related Issues (if applicable)

Documents the CMS changes in umbraco/Umbraco-CMS#23905, umbraco/Umbraco-CMS#23906, umbraco/Umbraco-CMS#23907 and umbraco/Umbraco-CMS#23908.

✅ Contributor Checklist

I've followed the Umbraco Documentation Style Guide and can confirm that:

• Code blocks are correctly formatted.
• Sentences are short and clear (preferably under 25 words).
• Passive voice and first-person language (“we”, “I”) are avoided.
• Relevant pages are linked.
• All links work and point to the correct resources.
• Screenshots or diagrams are included if useful.
• Any code examples or instructions have been tested.
• Typos, broken links, and broken images are fixed.

Product & Version (if relevant)

Umbraco CMS 19

Deadline (if relevant)

When the Umbraco 19 docs are published.

📚 Helpful Resources

• 🧾 Umbraco Contribution Guidelines
• ✍️ Umbraco Documentation Style Guide

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