feat(storage): 存储实例与 Alist 虚拟路径(迁移 0090、设置接口、注册表、vfs、健康检查)

- storage_instance 表 + secret 用途 storage_credential;令牌 / 密码 / 路径密码只写不读
- /storage-instances CRUD 与测试连接(版本、用户、根路径、容量);被库根引用不能删
- 远端路径 /@alist/<id>/<路径>,vfs 统一本地 / Alist 的 stat、列目录、建目录、读写、移动、删除
- 整理矩阵中涉及 Alist 的传输(storage/transfer.ts)与远端 ffprobe(直链只读头)
- 媒体库目录可登记在 Alist 上(不写哨兵,目录可访问即在线);健康检查列出存储实例

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Cxwgnn2pbzQ7rXv3rq7fei

packages/contracts/src/ops.ts

@@ -168,6 +168,7 @@ export const SecretPurpose = z.enum([
   "media_server_api_key",
   "metadata_api_key",
   "llm_api_key",
+  "storage_credential",
   "other",
 ]);
 export type SecretPurpose = z.infer<typeof SecretPurpose>;
@@ -448,7 +449,8 @@ export const SystemDisk = z.object({
 export type SystemDisk = z.infer<typeof SystemDisk>;
 
 export const SystemMount = z.object({
-  kind: z.enum(["library_root", "path_mapping"]),
+  /** storage_instance = Alist / OpenList 实例(连通 + 根路径可访问;令牌失效为 offline/auth) */
+  kind: z.enum(["library_root", "path_mapping", "storage_instance"]),
   id: z.string(),
   name: z.string(),
   path: z.string(),