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/App.tsx

@@ -142,7 +142,7 @@ function App() {
             </Button>
             <Button onClick={() => setIsAddOpen(true)}>
               <Plus className="h-4 w-4" />
-              {t("header.addProvider", { defaultValue: "添加供应商" })}
+              {t("header.addProvider")}
             </Button>
           </div>
         </div>
@@ -198,12 +198,11 @@ function App() {
 
       <ConfirmDialog
         isOpen={Boolean(confirmDelete)}
-        title={t("confirm.deleteProvider", { defaultValue: "删除供应商" })}
+        title={t("confirm.deleteProvider")}
         message={
           confirmDelete
             ? t("confirm.deleteProviderMessage", {
                 name: confirmDelete.name,
-                defaultValue: `确定删除 ${confirmDelete.name} 吗？`,
               })
             : ""
         }