Connect the theme to a Git repository, provisioning one if needed
Ensures the theme has a connected Git repository, creating and provisioning one when it doesn’t already have it.
Idempotent — an already-connected theme returns its repository unchanged, and one whose earlier provisioning failed has it retried. Safe to call twice.
Provisioning the upstream repository happens in the background, so a
freshly created connection reports status: provisioning and becomes
connected shortly after. Poll the git_versions operation, or retry
this one, to observe the change.
This connects themes that automatic provisioning deliberately skips — development themes among them — because an explicit request is a different intent from “provision every theme on creation”.