XY-931: [ELF benchmark P0] Add OpenMemory UI/export readback runner

[yvette-carlisle]

Summary:

• Add a dedicated OpenMemory export-helper readback probe under the mem0 baseline runner.
• Emit a durable typed blocker artifact for OpenMemory UI/export separately from local mem0 SDK get_all evidence.
• Update adapter manifest, benchmark reports, research JSON, README summary, and report assertions to preserve hosted Platform and optional graph-memory non-goals.

Validation:

• cargo make openmemory-ui-export-readback
• cargo make real-world-memory
• cargo make fmt
• cargo make lint-fix
• cargo make checks

Result:

• OpenMemory UI/export remains blocked with DOCKER_UNAVAILABLE_IN_BASELINE_RUNNER; SDK get_all evidence is not treated as UI/export evidence.