docs(avatar): document Nextcloud 25 avatar size normalization and dark-theme endpoints

[Copilot]

Nextcloud 25 changed generated avatar behavior (nextcloud/server#33752): deprecated sizes are clamped to supported values, and dark-theme variants are now available via dedicated routes.

Changes

• developer_manual/release_notes/previous/upgrade_to_25.rst — upgrade note under Back-end changes:

  • Sizes ≤ 64 → 64×64; sizes > 64 → 512×512
  • Dark-theme endpoints: /avatar/{userId}/{size}/dark, /avatar/guest/{guestName}/{size}/dark

• developer_manual/design/atomiccomponents.rst — brief .. note:: in the Avatar section covering the same size normalization and dark-theme variant availability

☑️ Resolves

fix #9590

🖼️ 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

[ChristophWurst]

Upgrade docs are obsolete by now but avatar sizes need docs

[ChristophWurst]

The documentation needed is the correct usage of the avatar API to avoid these: https://github.com/search?q=repo%3Anextcloud%2Fserver+%22Avatar+requested+in+deprecated+size%22&type=code

[skjnldsv]

@ChristophWurst we do not have those endpoint documented, only in the openapi.
You want them on phpdocs ?

[ChristophWurst]

If there's openapi docs with the two allowed sizes then this is already fine

[skjnldsv]

If there's openapi docs with the two allowed sizes then this is already fine
https://docs.nextcloud.com/server/latest/developer_manual/_static/openapi.html#/operations/core-avatar-get-avatar-dark

Closing then

[github-actions]

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• developer_manual/release_notes/previous/upgrade_to_25.rst

Last updated: Thu, 07 May 2026 10:02:03 GMT