fix(mount): load username from mount when testing without it

packages/trpc/src/services/mount.service.ts

@@ -151,12 +151,13 @@ export const mountService = {
         } catch (e) {
             return { ok: false, message: e instanceof Error ? e.message : "地址不合法" };
         }
-        // 编辑时密码留空：复用已存密文测连，避免每次重填
+        // 编辑时密码留空：复用已存密文测连，避免每次重填；用户名缺省也从挂载读取
         let password = input.password;
+        let username = input.username;
         let usedStored = false;
-        if (!password && input.mountId && userId) {
+        if (input.mountId && userId) {
             const existing = await mountDao.getByIdForUser(input.mountId, userId);
-            if (existing?.secretEnc) {
+            if (!password && existing?.secretEnc) {
                 try {
                     password = decryptSecret(existing.secretEnc);
                     usedStored = true;
@@ -164,11 +165,12 @@ export const mountService = {
                     // 密钥不一致等，退回空密码
                 }
             }
+            if (!username && existing?.username) username = existing.username;
         }
         try {
             const client = createWebdav({
                 baseUrl: input.baseUrl,
-                username: input.username,
+                username,
                 password,
             });
             const root = normalizeWebdavPath(input.rootPath || "/");