Operator-branded OpenGraph share cards

[ashwin47]

What

Shared links to a Sabha instance now unfurl with the operator's own identity instead of a Sabha marketing image. When someone pastes their community's link into Slack, Discord, or iMessage, the preview card shows the operator's uploaded logo (or the Sabha mark as a fallback) above their account name, on a clean brand background with a small "powered by sabha" footer.

Why

The og:image tag previously hardcoded a sabha.co marketing image on every self-hosted and in-app surface. A self-hoster who had set their own app name, theme, and logo still saw a literal sabha.co ad on the one surface that matters most — the share card a prospective member sees first. The card is now rendered per-instance so it reflects whoever owns the surface.

How it works

• og:image points at a new account-scoped endpoint that renders a 1200×630 PNG on the fly via libvips (the same image stack already used for logo variants — no ImageMagick dependency).
• Current.account resolves the right identity automatically: the singleton account when self-hosted, the workspace account when running multi-tenant. The same code path therefore produces the operator's name on self-hosted and the workspace name inside a SaaS workspace.
• The card is publicly cacheable with an ETag and a updated_at-based cache-buster, mirroring the existing logo endpoint.
• The public sabha.co marketing layout is intentionally left untouched — it keeps its hand-made card.

Testing

• Model, controller, and integration coverage for the rendered card, the logo-vs-stock-mark branches, the blank-name fallback, public caching, and 304 revalidation.
• Full single-tenant and multi-tenant suites pass; the card was also rendered live inside a real workspace tenant to confirm it picks up the workspace name.