docs: add Nextcloud Office (Euro-Office) section to admin manual

[chrip]

☑️ Resolves

relates to Nextcloud Office (Euro-Office) becoming the default office solution in Nextcloud

Summary

Nextcloud Office, powered by Euro-Office Document Server, is becoming the default office
solution in Nextcloud. This PR adds a dedicated documentation section and restructures the
Office navigation to present both solutions clearly.

Navigation changes:

• office/index.rst now introduces both Nextcloud Office and Collabora Online
• New euro-office/ section under office/ for Nextcloud Office documentation
• New collabora_online.rst wrapper so existing Collabora docs appear under
  "Collabora Online" in the sidebar — no files moved, no redirects needed

New pages (admin_manual/office/euro-office/):

• index.rst — Nextcloud Office section overview
• installation.rst — installation overview with supported platform table
• installation_ubuntu.rst — step-by-step guide for Ubuntu 24.04 LTS
• installation_debian.rst — step-by-step guide for Debian 12 (Bookworm)
• installation_docker.rst — Docker installation with full environment variable reference
• configuration.rst — connector app install, admin UI settings (matching actual
  settings.php structure), Docker Compose internal URL example, occ commands,
  config.php reference

All installation guides are verified on real machines. Configuration page field labels
match the actual admin UI from the eurooffice app source.

🖼️ Screenshots

✅ Checklist

• I have built the documentation locally and reviewed the output
• Screenshots are included for visual changes
• I have not moved or renamed pages (or added a redirect if I did)
• I have run codespell or similar and addressed any spelling issues

Assisted-by: claude-code:claude-sonnet-4-6

[github-actions]

📖 Documentation Preview

🔍 Open preview →

📄 8 changed documentation pages

• admin_manual/office/collabora_online.rst
• admin_manual/office/euro-office/configuration.rst
• admin_manual/office/euro-office/index.rst
• admin_manual/office/euro-office/installation.rst
• admin_manual/office/euro-office/installation_debian.rst
• admin_manual/office/euro-office/installation_docker.rst
• admin_manual/office/euro-office/installation_ubuntu.rst
• admin_manual/office/index.rst

Last updated: Wed, 17 Jun 2026 12:15:26 GMT

[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/documentation/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22

[susnux]

@chrip would you mind resolving the issue with the OCC commands? Currently the CI is read on main:

./admin_manual/office/euro-office/configuration.rst does not use the 'sudo -E -u www-data php occ' syntax in some places which is required.

(it was already red in this PR when merging 🙈 )

[juliusknorr]

#15215

[github-actions]

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