[Enhancement]: Use custom logo for Open Graph/link preview image instead of default /logo.png

[CallMeLeon167]

Current Behavior

When setting a custom logo (e.g. via the CUSTOM_LOGO environment variable), the logo is correctly displayed in the Web UI. However, when sharing a link to the instance (e.g. via messenger or social media), the generated link preview (Open Graph / card image) does not use this custom logo. Instead, it falls back to loading /logo.png, which ignores the configured custom logo entirely.

Proposed Improvement

Introduce a separate configuration variable (e.g. CUSTOM_OG_IMAGE or similar) that allows setting a dedicated image specifically for the Open Graph/link preview card. Alternatively, the existing CUSTOM_LOGO variable could simply be reused/referenced for the OG image meta tag as well, so both the Web UI and the shared link preview stay consistent without requiring a separate file at /logo.png

Motivation

Currently, users who configure a custom logo end up with inconsistent branding: the Web UI shows the custom logo, but any shared link preview still shows the default/hardcoded /logo.png. This is confusing for white-labeled or self-hosted instances where full branding consistency is expected — especially when links are shared externally and represent the "public face" of the instance.

Area

Web UI

Additional Context

No response

Instance Type

Self-hosted instance

[Skyfay]

Hey @CallMeLeon167

Thank you for creating this issue.

That's something that should be easy to implement. I'll aim to include it in the next release.

Thanks :)