Defer federated mode topology deployment coverage

Context

The Memory Core deployment strategy currently defaults to the "unified" mode (shared Chroma instance), which serves as the product-path default.

As tracked in #10950 (topology matrix coverage), the "federated" mode topology (separate Chroma instances) has been demoted to a non-MVP diagnostic track. This ticket serves to explicitly defer the product claims and test coverage for the federated cloud topology (#10009).

The Problem

Retiring or fully supporting the federated topology as a product path requires an explicit ruling from the maintainer (@tobiu). Until that ruling is made, we are deferring federated mode deployment coverage from the primary integration pipeline to prevent over-testing non-product paths or creating stale product claims without evidence.

Acceptance Criteria

• Maintainer (@tobiu) provides an explicit architectural ruling on whether the federated cloud topology (#10009) should be fully retired or maintained as an active non-MVP diagnostic track.
• If retired, deployment documentation and test fixtures are purged of federated mode references.
• If maintained, an explicit diagnostic suite is documented and maintained outside the test-integration-unified product path.

Related

• Related to #10950
• Related to #10009
• Parent: #10945