fix(api): localize service-layer ValueError messages to Chinese

So str(exc) passthrough on scripts, batch, sync, and schedule routes
returns Chinese without relying only on the HTTP detail translation layer.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/infrastructure/ssh/asyncssh_pool.py

@@ -238,7 +238,7 @@ class AsyncSSHPool:
         elif server.ssh_key_path:
             connect_kwargs["client_keys"] = [server.ssh_key_path]
         else:
-            raise ValueError(f"No valid SSH credentials for server {server.id} ({server.name})")
+            raise ValueError(f"服务器 {server.id}（{server.name}）没有可用的 SSH 凭据")
 
         try:
             conn = await asyncssh.connect(**connect_kwargs)