Per-tenant configuration layer

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Problem: A customer needs their own equivalent of an autonomy/config setting, scoped strictly to their own rented repo, independent of gittensory's own configuration.

Area: AMS / Miner

Proposal: Build a per-tenant configuration layer covering autonomy level (per #4782) and any repo-specific execution preferences, stored and resolved independently per tenant.

Deliverables:

• A configuration mechanism a customer can set for their own rented repo, with no ability to affect any other tenant's configuration.

Acceptance criteria:

• Two different tenants can hold different, independent configurations for the same underlying loop mechanics with no cross-contamination.

Boundaries:

• Blocked on Third-party autonomy & security governance spec #4782 and Multi-tenant hosted architecture spec #4783.

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Part of #4778.

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JSO-3459