Build an admin API/CLI to provision a new customer deployment

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Problem: There's no admin API or CLI today to provision a new customer's deployment — every step of standing up a new instance is manual.

Area: ORB / Fleet ops

Proposal: Build an internal admin tool that can provision a new tenant/instance end-to-end, building on the fleet/config work elsewhere in this category.

Deliverables:

• A working internal provisioning tool.

Boundaries:

• Internal/admin-only — this is not the customer-facing self-serve signup flow (see the Onboarding category), which is a separate, customer-safe surface.

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JSO-3561