refactor(api): 渠道与存储管理端点通用化，端点层零目标特色

- schemas 新增公共 ManageRequest(target+action+params) 与 StorageAction 词汇表
- endpoint 层收敛为 POST /notification/manage、/storage/manage 两个通用接口，
  不再定义任何渠道/存储特定的名称、参数与响应字段，前端上送参数原样透传
- chain 层 manage_channel/manage_storage 接受字符串标识纯透明转发，
  StorageChain 移除全部特色管理方法
- FileManagerModule 新增 storage_manage 统一入口，模块返回归一化为
  {success, message, data}；wechatclawbot channel_manage 同步归一化，
  路由标识兼容枚举名/值/对象
- dashboard 与 agentopsassistant 的用量查询改走 manage_storage(usage)
- 新增 10 项存储契约守护测试，通知侧补充 3 项链透传与字符串路由测试，
  API 守护测试对 ManageRequest 开放映射按设计豁免

app/api/endpoints/dashboard.py

@@ -13,6 +13,7 @@ from app.application.security.access import verify_apitoken
 from app.db import get_db
 from app.db.models.transferhistory import TransferHistory
 from app.api.deps import get_current_active_superuser
+from app.schemas.types import StorageAction
 from app.application.directory import DirectoryHelper
 from app.scheduler import Scheduler
 from app.adapters.system.host import SystemUtils
@@ -65,7 +66,8 @@ def _build_storage() -> schemas.Storage:
         return schemas.Storage(total_storage=total, used_storage=total - available)
     storages = set([d.library_storage for d in dirs if d.library_storage])
     for _storage in storages:
-        _usage = StorageChain().storage_usage(_storage)
+        _result = StorageChain().manage_storage(storage=_storage, action=StorageAction.USAGE.value)
+        _usage = _result.get("data") if _result.get("success") else None
         if _usage:
             total += _usage.total
             available += _usage.available