Issue live connection credentials for a service in an environment

Provisions the per-tenant database if it does not exist yet, then returns the connection variables in plaintext — the same values a deployment gets injected at runtime.

This is a POST because it is not a read. It creates a database as a side effect, and its response is a live credential: a GET would be prefetchable, cacheable, and liable to end up in a proxy access log with the whole connection in the URL's neighbourhood. Nothing about it is safe or idempotent in the HTTP sense.

Intended for callers that need to connect an application to a managed service — the console's own deploy path does this in-process; external plugins reach it here. For inspecting configuration, use the masked bulk read or the single-variable reveal instead.