feat: manually mirror opencoze's code from bytedance

Change-Id: I09a73aadda978ad9511264a756b2ce51f5761adf

backend/pkg/i18n/i18n.go

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2025 coze-dev Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package i18n
+
+import (
+	"context"
+)
+
+type Locale string
+
+const (
+	LocaleEN Locale = "en-US"
+	LocaleZH Locale = "zh-CN"
+)
+
+const key = "i18n.locale.key"
+
+func SetLocale(ctx context.Context, locale string) context.Context {
+	return context.WithValue(ctx, key, locale)
+}
+
+func GetLocale(ctx context.Context) Locale {
+	locale := ctx.Value(key)
+	if locale == nil {
+		return LocaleEN
+	}
+
+	switch locale.(string) {
+	case "en-US":
+		return LocaleEN
+	case "zh-CN":
+		return LocaleZH
+	default:
+		return LocaleEN
+	}
+}