fix(api,panel): refuse file operations on a server without a world volume (#58)

Live: the files page against a server whose world claim does not exist (never
started, or reaped) created a Job whose Pod stayed Pending on
FailedScheduling (persistentvolumeclaim not found) until the executor's 90s
wait expired — a 90s spinner answered by a misleading 504 files_timeout, for
a request that is knowably impossible. Backup and restore have refused this
shape with 409 no_world_volume since the #42 round; the file routes now run
the same gate before any Job is created, and the panel maps the code to a
localized message (it previously fell back to the English server text).

panel/src/i18n/resources/en-US/errors.json

@@ -14,6 +14,7 @@
   "console_unavailable": "Can't reach the server console right now — try again shortly.",
   "no_backup": "There's no restorable backup for this server yet.",
   "not_stopped": "Stop the server completely before restoring — a restore overwrites the live world volume.",
+  "no_world_volume": "This server has no world volume yet — start it once so it is created, then retry.",
   "restore_unavailable": "Restore isn't available right now — try again later.",
   "session_expired": "Your session expired — please sign in again.",
   "forbidden": "You are not allowed to do that.",

panel/src/i18n/resources/zh-CN/errors.json

@@ -14,6 +14,7 @@
   "console_unavailable": "暂时无法连接服务器控制台，请稍后重试。",
   "no_backup": "这台服务器暂时没有可回档的备份。",
   "not_stopped": "回档会覆盖世界的实时存储卷，请先把服务器完全停止再回档。",
+  "no_world_volume": "这台服务器还没有世界卷——先启动一次让它创建，然后再试。",
   "restore_unavailable": "回档功能当前不可用，请稍后再试。",
   "session_expired": "会话已过期——请重新登录。",
   "forbidden": "你无权执行此操作。",

panel/src/lib/api.ts

@@ -678,6 +678,8 @@ export function humanizeError(e: unknown): string {
       return t("no_backup");
     case "not_stopped":
       return t("not_stopped");
+    case "no_world_volume":
+      return t("no_world_volume");
     case "restore_unavailable":
       return t("restore_unavailable");
     default: