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/components/providers/ProviderCard.tsx

@@ -104,7 +104,7 @@ export function ProviderCard({
               "mt-1 flex h-8 w-8 items-center justify-center rounded-md border border-transparent text-muted-foreground transition-colors hover:border-muted hover:text-foreground",
               dragHandleProps?.isDragging && "border-primary text-primary",
             )}
-            aria-label={t("provider.dragHandle", { defaultValue: "拖拽排序" })}
+            aria-label={t("provider.dragHandle")}
             {...(dragHandleProps?.attributes ?? {})}
             {...(dragHandleProps?.listeners ?? {})}
           >
@@ -118,7 +118,7 @@ export function ProviderCard({
               </h3>
               {isCurrent && (
                 <span className="rounded-full bg-green-500/10 px-2 py-0.5 text-xs font-medium text-green-500 dark:text-green-400">
-                  {t("provider.currentlyUsing", { defaultValue: "当前使用" })}
+                  {t("provider.currentlyUsing")}
                 </span>
               )}
             </div>