feat: Support i18n

qwen3-tts-frontend/src/locales/en-US/user.json

@@ -0,0 +1,59 @@
+{
+  "userManagement": "User Management",
+  "userList": "User List",
+  "userId": "User ID",
+  "username": "Username",
+  "role": "Role",
+  "createdAt": "Created At",
+  "lastLogin": "Last Login",
+  "actions": "Actions",
+  "addUser": "Add User",
+  "editUser": "Edit User",
+  "deleteUser": "Delete User",
+  "deleteUserConfirm": "Are you sure you want to delete user {{username}}?",
+  "userDeleted": "User deleted",
+  "userAdded": "User added",
+  "userUpdated": "User updated",
+  "userOperationFailed": "User operation failed",
+  "roleAdmin": "Admin",
+  "roleUser": "User",
+  "password": "Password",
+  "newPassword": "New Password",
+  "confirmPassword": "Confirm Password",
+  "passwordMismatch": "Passwords do not match",
+  "changePassword": "Change Password",
+  "passwordChanged": "Password changed",
+  "noUsers": "No users",
+  "searchUsers": "Search Users",
+  "filterByRole": "Filter by Role",
+  "allRoles": "All Roles",
+  "createUser": "Create User",
+  "loadUsersFailed": "Failed to load user list",
+  "userUpdateSuccess": "User updated successfully",
+  "userCreateSuccess": "User created successfully",
+  "operationFailed": "Operation failed",
+  "userDeleteSuccess": "User deleted successfully",
+  "deleteFailed": "Delete failed",
+  "createUserDialog": "Create User",
+  "editUserDialog": "Edit User",
+  "createUserDescription": "Create new user and configure basic information",
+  "editUserDescription": "Modify user information and permission settings",
+  "email": "Email",
+  "passwordOptional": "Password (leave blank to keep unchanged)",
+  "isActive": "Active Status",
+  "isSuperuser": "Super Administrator",
+  "canUseLocalModel": "Local Model Permission",
+  "canUseLocalModelDescription": "Allow user to use local TTS model",
+  "saving": "Saving...",
+  "active": "Active",
+  "inactive": "Inactive",
+  "superuser": "Super Admin",
+  "normalUser": "Normal User",
+  "localModelPermission": "Local Model",
+  "noPermission": "None",
+  "validation": {
+    "usernameMinLength": "Username must be at least 3 characters",
+    "usernameMaxLength": "Username cannot exceed 20 characters",
+    "emailInvalid": "Please enter a valid email address"
+  }
+}