refactor: 优化多语言结构并新增远端语言包加载能力

1. 扁平化多语言文件层级，移除嵌套的命名空间
2. 更新组件内多语言调用路径，适配新的语言包结构
3. 重构HTTP请求错误处理逻辑
4. 新增remote-only模式的远端语言包加载器
5. 新增多语言数据源remote-only配置项

lang/en-us/components-diy/diy-index-page.js

@@ -1,14 +1,10 @@
 export const lang = {
-	'components-diy': {
-		diyIndexPage: {
-			// Home (default category name)
-			home: 'Home',
-			// Sales text: Sold X units
-			soldCount: 'Sold {count}{unit}',
-			// Sales unit: piece
-			soldUnit: 'pcs',
-			// Empty state prompt when no goods in category
-			noGoodsInCategory: 'No goods in this category',
-		},
-	},
+	// Home (default category name)
+	home: 'Home',
+	// Sales text: Sold X units
+	soldCount: 'Sold {count}{unit}',
+	// Sales unit: piece
+	soldUnit: 'pcs',
+	// Empty state prompt when no goods in category
+	noGoodsInCategory: 'No goods in this category',
 }