chore(data): 落库 auth 多账号结构的运行时迁移结果

data/config.json 由代码在启动时自动从单账号迁移为 accounts[] 结构
（admin 保留原 salt/hash 未重置 + 播种只读访客 guest，guest_seeded=true）。
本地与线上运行时早已是此结构，只是此前未提交，导致工作区长期显示为已修改。
（data/config.json 为仓库跟踪的配置文件，非运行时业务库，提交无副作用。）

Co-authored-by: CodeBuddy

data/config.json

@@ -2,7 +2,26 @@
   "auth": {
     "username": "admin",
     "salt": "rentos-2026",
-    "password_hash": "3d4e486a8040fa5356c900c5485b93d4573c9d3b4a128dc40a91234fd4de79b7"
+    "password_hash": "3d4e486a8040fa5356c900c5485b93d4573c9d3b4a128dc40a91234fd4de79b7",
+    "accounts": [
+      {
+        "username": "admin",
+        "salt": "rentos-2026",
+        "password_hash": "3d4e486a8040fa5356c900c5485b93d4573c9d3b4a128dc40a91234fd4de79b7",
+        "role": "admin",
+        "note": "系统管理员",
+        "created_at": "2026-10-13 11:55:31"
+      },
+      {
+        "username": "guest",
+        "salt": "d232110691983659",
+        "password_hash": "a588e529a46faffc0fcd660b9a1ee5546297fbbb48ecfb979e8a7199e48750f9",
+        "role": "viewer",
+        "note": "只读访客",
+        "created_at": "2026-10-13 11:55:31"
+      }
+    ],
+    "guest_seeded": true
   },
   "notify": {
     "enabled": true,