feat(usage): claude-desktop filter and pricing-model audit display

- add claude-desktop to AppType/KNOWN_APP_TYPES and the dashboard app
  filter; it was hidden because its rows looked like pure failure
  noise, which was the app_type attribution bug fixed on the backend
- request detail panel now shows the requested model and the pricing
  model when they differ from the response model, making route-takeover
  bills auditable from the UI
- locale keys added for zh/en/ja/zh-TW

src/components/usage/RequestDetailPanel.tsx

@@ -111,6 +111,28 @@ export function RequestDetailPanel({
                   {t("usage.model", "模型")}
                 </dt>
                 <dd className="font-mono">{request.model}</dd>
+                {request.requestModel &&
+                  request.requestModel !== request.model && (
+                    <>
+                      <dt className="mt-1 text-muted-foreground">
+                        {t("usage.requestModel", "请求模型")}
+                      </dt>
+                      <dd className="font-mono text-xs">
+                        {request.requestModel}
+                      </dd>
+                    </>
+                  )}
+                {request.pricingModel &&
+                  request.pricingModel !== request.model && (
+                    <>
+                      <dt className="mt-1 text-muted-foreground">
+                        {t("usage.pricingModel", "计价模型")}
+                      </dt>
+                      <dd className="font-mono text-xs">
+                        {request.pricingModel}
+                      </dd>
+                    </>
+                  )}
               </div>
               <div>
                 <dt className="text-muted-foreground">