feat: OpenCode执行层试点 — 补测试5个 + list_objectives隔离修复

- OpenCode执行模式: 补 test_maps.py 5个测试(create_objective/snapshot隔离/entity注入/跨企业)
- OpenCode诚实标注: list_objectives 后端漏entity过滤 → 修复(跨企业返回空)
- 记忆层闭环: Hermes验证(pytest 536 passed) + 技能已更新(opencode-independent-review 双角色)
- 执行层试点验证: OpenCode能写代码+发现后端缺口, 最小闭环跑通

backend/app/api/objectives.py

@@ -13,7 +13,10 @@ router = APIRouter(prefix="/api/cma/maps", tags=["战略地图目标"],
 
 @router.get("/{map_id}/objectives")
 def list_objectives(map_id: int, db: Session = Depends(get_db), entity_id: int = Depends(get_entity_id)):
-    """获取某地图下的所有目标"""
+    """获取某地图下的所有目标（账套隔离: 跨企业返回空, OpenCode执行层发现）"""
+    m = db.query(StrategicMap).filter(StrategicMap.id == map_id, StrategicMap.entity_id == entity_id).first()
+    if not m:
+        return {"data": []}
     objs = db.query(MapObjective).filter(
         MapObjective.map_id == map_id
     ).order_by(MapObjective.sort_order).all()