feat: 新增多语言文案与组件国际化适配

本次提交完成了大量多语言相关的新增与优化工作：
1. 新增充值、案例、会员资产、订单等页面的中文/英文翻译文案
2. 新增企业微信客服、时间选择、支付弹窗等组件的多语言包
3. 优化工具函数与自定义页面的多语言适配，替换硬编码提示文案
4. 新增会员等级规则、积分商品、退款管理等页面的国际化支持
5. 修复企业微信JS-SDK的错误提示文案硬编码问题

lang/en-us/components/ns-form.js

@@ -0,0 +1,26 @@
+export const lang = {
+	// ===== ns-form component =====
+	'nsForm': {
+		// Selector placeholders
+		selectPlaceholder: 'Please select',
+		selectProvinceCity: 'Please select province and city',
+		selectProvinceCityDistrict: 'Please select province, city and district',
+
+		// Validation - required
+		pleaseInput: 'Please enter {title}',
+		pleaseSelect: 'Please select {title}',
+		pleaseSelectAtLeastOne: 'Please select at least one {title}',
+		pleaseUploadAtLeastOne: 'Please upload at least one {title}',
+
+		// Validation - format
+		idCardInvalid: 'Invalid ID card number',
+		mobileInvalid: 'Invalid mobile number',
+
+		// Validation - range
+		endDateBeforeStartDate: 'End date cannot be earlier than start date',
+		endTimeBeforeStartTime: 'End time must be later than start time',
+
+		// Image upload
+		maxUploadImages: 'Upload up to {max} images',
+	}
+}