feat: target-ontology-adapter §8 Cross-capability integration tests

[deanban]

Neo4j-backed integration tests crossing the loader, materializer, planner-contract provenance/pin types, registry version routing, and adapter-supplied vs deferred enrichment paths.

Tracking: #97. Source: openspec/changes/target-ontology-adapter/tasks.md §8.

Tasks

• 8.1 Round-trip: golden manifest -> Neo4j -> reconstructed DTOs
• 8.2 target_schema_snapshot_hash provenance byte-identity
• 8.3 Pin-invalidation on schema drift
• 8.3a Pin-invalidation on card-version drift only
• 8.4 Lazy subset: selected_refs materialization + stable subset hash
• 8.5 Multi-adapter coexistence (no entity collisions)
• 8.5a Version-aware registry routing across two OMOP ranges
• 8.6 Adapter-supplied vs deferred enrichment record routing
• 8.7 Operator skip_facets opt-out integration