feat(storage): implement user-group level file management dashboard and APIs

- Expose user-scoped CRUD APIs under `/api/v1/upload` (my files query, stats, rename, delete)
- Update backend handlers and routers with ownership validation checks
- Create a dedicated frontend personal file manager card-list and upload button under `/files`
- Add comprehensive backend test coverage and update API docs

frontend/components/layout/sidebar.tsx

@@ -68,6 +68,7 @@ import {usePublicConfig} from "@/hooks/use-public-config"
 const data = {
   navMain: [
     { title: "首页", url: "/home", icon: Home },
+    { title: "我的文件", url: "/files", icon: FolderOpen },
   ],
   admin: [
     { title: "用户管理", url: "/admin/users", icon: UserRound },