feat: Phase 5A — Engineering V1 foundation

First slice of the Engineering V1 sprint. Lays the schema + lifecycle
plumbing so the 10 canonical queries, memory graduation, and conflict
detection can land cleanly on top.

Schema (src/atocore/models/database.py):
- conflicts + conflict_members tables per conflict-model.md (with 5
  indexes on status/project/slot/members)
- memory_audit.entity_kind discriminator — same audit table serves
  both memories ("memory") and entities ("entity"); unified history
  without duplicating infrastructure
- memories.graduated_to_entity_id forward pointer for graduated
  memories (M → E transition preserves the memory as historical
  pointer)

Memory (src/atocore/memory/service.py):
- MEMORY_STATUSES gains "graduated" — memory-entity graduation flow
  ready to wire in Phase 5F

Engineering service (src/atocore/engineering/service.py):
- RELATIONSHIP_TYPES organized into 4 families per ontology-v1.md:
  + Structural: contains, part_of, interfaces_with
  + Intent: satisfies, constrained_by, affected_by_decision,
    based_on_assumption (new), supersedes
  + Validation: analyzed_by, validated_by, supports (new),
    conflicts_with (new), depends_on
  + Provenance: described_by, updated_by_session (new),
    evidenced_by (new), summarized_in (new)
- create_entity + create_relationship now call resolve_project_name()
  on write (canonicalization contract per doc)
- Both accept actor= parameter for audit provenance
- _audit_entity() helper uses shared memory_audit table with
  entity_kind="entity" — one observability layer for everything
- promote_entity / reject_entity_candidate / supersede_entity —
  mirror the memory lifecycle exactly (same pattern, same naming)
- get_entity_audit() reads from the shared table filtered by
  entity_kind

API (src/atocore/api/routes.py):
- POST /entities/{id}/promote (candidate → active)
- POST /entities/{id}/reject (candidate → invalid)
- GET /entities/{id}/audit (full history for one entity)
- POST /entities passes actor="api-http" through

Tests: 317 → 326 (9 new):
- test_entity_project_canonicalization (p04 → p04-gigabit)
- test_promote_entity_candidate_to_active
- test_reject_entity_candidate
- test_promote_active_entity_noop (only candidates promote)
- test_entity_audit_log_captures_lifecycle (before/after snapshots)
- test_new_relationship_types_available (6 new types present)
- test_conflicts_tables_exist
- test_memory_audit_has_entity_kind
- test_graduated_status_accepted

What's next (5B-5I, deferred): entity triage UI tab, core structure
queries, the 3 killer queries, memory graduation script, conflict
detection, MCP + context pack integration. See plan file.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/atocore/api/routes.py

@@ -1286,6 +1286,7 @@ def api_create_entity(req: EntityCreateRequest) -> dict:
             status=req.status,
             confidence=req.confidence,
             source_refs=req.source_refs,
+            actor="api-http",
         )
     except ValueError as e:
         raise HTTPException(status_code=400, detail=str(e))
@@ -1326,6 +1327,34 @@ def api_list_entities(
     }
 
 
+@router.post("/entities/{entity_id}/promote")
+def api_promote_entity(entity_id: str) -> dict:
+    """Promote a candidate entity to active (Phase 5 Engineering V1)."""
+    from atocore.engineering.service import promote_entity
+    success = promote_entity(entity_id, actor="api-http")
+    if not success:
+        raise HTTPException(status_code=404, detail=f"Entity not found or not a candidate: {entity_id}")
+    return {"status": "promoted", "id": entity_id}
+
+
+@router.post("/entities/{entity_id}/reject")
+def api_reject_entity(entity_id: str) -> dict:
+    """Reject a candidate entity (Phase 5)."""
+    from atocore.engineering.service import reject_entity_candidate
+    success = reject_entity_candidate(entity_id, actor="api-http")
+    if not success:
+        raise HTTPException(status_code=404, detail=f"Entity not found or not a candidate: {entity_id}")
+    return {"status": "rejected", "id": entity_id}
+
+
+@router.get("/entities/{entity_id}/audit")
+def api_entity_audit(entity_id: str, limit: int = 100) -> dict:
+    """Return the audit history for a specific entity."""
+    from atocore.engineering.service import get_entity_audit
+    entries = get_entity_audit(entity_id, limit=limit)
+    return {"entity_id": entity_id, "entries": entries, "count": len(entries)}
+
+
 @router.get("/entities/{entity_id}")
 def api_get_entity(entity_id: str) -> dict:
     """Get an entity with its relationships and related entities."""