Get Active Provider

Tiny, cheap endpoint that omicos-core polls to decide whether to add the markdown-image directive to the system prompt. No config or token in the response — just the routing intent.

When there's NO saved row (truly unset), a paid user on the cloud web client (X-Client-Platform: web) defaults to 'cloud' so figures offload without a manual toggle; every other unset case stays 'off' (fail closed). An EXPLICIT row is always honored verbatim (never override github/off).