Optional multi-tenant accounts or shareable read-only stats access per site key

Hi everybody,

As an other option to my FR "scoped API Keys", it would be relay great to make Cap more multi tenant compatible.

Problem

Cap Standalone only supports a single ADMIN_KEY for the whole dashboard — there's no way to give a client direct, restricted access to just their own site key's data. For agencies/hosters running one Cap instance across many client sites, this means clients can never see their own stats directly; the operator either has to share the full admin credential (unacceptable — exposes every other client's data too) or build custom glue code to proxy just their numbers elsewhere.

Proposed feature

Either of the following would solve this well:

Lightweight user accounts scoped to specific site keys — in addition to the single ADMIN_KEY, allow creating restricted logins tied to one or more site keys, so a client could log in directly and see only their own stats/config. A simpler alternative: a shareable, read-only stats link/token per site key (no login required) that could be handed out or embedded, showing just that key's solve/verification numbers over time — no accounts needed at all.

Either approach removes the need for third parties to build and maintain their own proxy view just to give clients basic visibility into their own numbers.

Example use case Agency/reseller runs one Cap instance for many client sites, integrated through a shared WordPress plugin. Clients could get direct visibility into their own solve/verification stats — either via a scoped login or a shareable link — without the agency needing to build a custom stats view on top of the API. Why this matters

This would make Cap self-service-friendly for end clients in agency/hosting setups, without requiring every operator to build the same "show me my own numbers" feature independently, like I planed in my other feature request.