i18n: complete internationalization for provider and usage query panels

- Add 45+ new translation keys for usage query and usage script features
- Fix duplicate provider object in translation files that caused missing translations
- Remove all hardcoded Chinese text and defaultValue fallbacks from components
- Add proper translations for:
  * Usage footer (query status, plan usage display)
  * Usage script modal (script editor, validation, test controls)
  * Provider forms (basic fields, endpoints, model selectors)
  * Provider dialogs (add/edit hints and titles)

Modified 16 files:
- 2 translation files (zh.json, en.json)
- 14 component files (removed defaultValue, added t() calls)

All UI text now properly supports Chinese/English switching.

src/i18n/locales/zh.json

@@ -73,13 +73,15 @@
     "sortUpdateFailed": "排序更新失败",
     "configureUsage": "配置用量查询",
     "name": "供应商名称",
+    "namePlaceholder": "例如：Claude 官方",
     "websiteUrl": "官网链接",
     "configJson": "配置 JSON",
     "writeCommonConfig": "写入通用配置",
     "editCommonConfigButton": "编辑通用配置",
     "configJsonHint": "请填写完整的 Claude Code 配置",
     "editCommonConfigTitle": "编辑通用配置片段",
-    "editCommonConfigHint": "通用配置片段将合并到所有启用它的供应商配置中"
+    "editCommonConfigHint": "通用配置片段将合并到所有启用它的供应商配置中",
+    "addProvider": "添加供应商"
   },
   "notifications": {
     "providerSaved": "供应商配置已保存",
@@ -297,6 +299,48 @@
     "other": "其他",
     "hint": "选择预设后可继续调整下方字段。"
   },
+  "usage": {
+    "queryFailed": "查询失败",
+    "refreshUsage": "刷新用量",
+    "planUsage": "套餐用量",
+    "invalid": "已失效",
+    "total": "总：",
+    "used": "使用：",
+    "remaining": "剩余："
+  },
+  "usageScript": {
+    "title": "配置用量查询",
+    "enableUsageQuery": "启用用量查询",
+    "presetTemplate": "预设模板",
+    "queryScript": "查询脚本（JavaScript）",
+    "timeoutSeconds": "超时时间（秒）",
+    "scriptHelp": "脚本编写说明：",
+    "configFormat": "配置格式：",
+    "extractorFormat": "extractor 返回格式（所有字段均为可选）：",
+    "tips": "💡 提示：",
+    "testing": "测试中...",
+    "testScript": "测试脚本",
+    "format": "格式化",
+    "saveConfig": "保存配置",
+    "scriptEmpty": "脚本配置不能为空",
+    "mustHaveReturn": "脚本必须包含 return 语句",
+    "testSuccess": "测试成功！",
+    "testFailed": "测试失败",
+    "formatSuccess": "格式化成功",
+    "formatFailed": "格式化失败",
+    "variablesHint": "支持变量: {{apiKey}}, {{baseUrl}} | extractor 函数接收 API 响应的 JSON 对象",
+    "fieldIsValid": "• isValid: 布尔值，套餐是否有效",
+    "fieldInvalidMessage": "• invalidMessage: 字符串，失效原因说明（当 isValid 为 false 时显示）",
+    "fieldRemaining": "• remaining: 数字，剩余额度",
+    "fieldUnit": "• unit: 字符串，单位（如 \"USD\"）",
+    "fieldPlanName": "• planName: 字符串，套餐名称",
+    "fieldTotal": "• total: 数字，总额度",
+    "fieldUsed": "• used: 数字，已用额度",
+    "fieldExtra": "• extra: 字符串，扩展字段，可自由补充需要展示的文本",
+    "tip1": "• 变量 {{apiKey}} 和 {{baseUrl}} 会自动替换",
+    "tip2": "• extractor 函数在沙箱环境中执行，支持 ES2020+ 语法",
+    "tip3": "• 整个配置必须用 () 包裹，形成对象字面量表达式"
+  },
   "kimiSelector": {
     "modelConfig": "模型配置",
     "mainModel": "主模型",