refactor(settings): split Advanced tab into Proxy tab and move Pricing to Usage

Extract proxy-related accordion items (Local Proxy, Failover, Rectifier,
Global Outbound Proxy) into a dedicated Proxy tab via ProxyTabContent
component. Move Pricing config panel to UsageDashboard as a collapsible
accordion. This reduces SettingsPage from ~716 to ~426 lines and improves
settings discoverability with a 5-tab layout: General | Proxy | Advanced |
Usage | About.

src/components/usage/UsageDashboard.tsx

@@ -8,10 +8,23 @@ import { ProviderStatsTable } from "./ProviderStatsTable";
 import { ModelStatsTable } from "./ModelStatsTable";
 import type { TimeRange } from "@/types/usage";
 import { motion } from "framer-motion";
-import { BarChart3, ListFilter, Activity, RefreshCw } from "lucide-react";
+import {
+  BarChart3,
+  ListFilter,
+  Activity,
+  RefreshCw,
+  Coins,
+} from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { useQueryClient } from "@tanstack/react-query";
 import { usageKeys } from "@/lib/query/usage";
+import {
+  Accordion,
+  AccordionContent,
+  AccordionItem,
+  AccordionTrigger,
+} from "@/components/ui/accordion";
+import { PricingConfigPanel } from "@/components/usage/PricingConfigPanel";
 
 export function UsageDashboard() {
   const { t } = useTranslation();
@@ -129,6 +142,31 @@ export function UsageDashboard() {
           </motion.div>
         </Tabs>
       </div>
+
+      {/* Pricing Configuration */}
+      <Accordion type="multiple" defaultValue={[]} className="w-full space-y-4">
+        <AccordionItem
+          value="pricing"
+          className="rounded-xl glass-card overflow-hidden"
+        >
+          <AccordionTrigger className="px-6 py-4 hover:no-underline hover:bg-muted/50 data-[state=open]:bg-muted/50">
+            <div className="flex items-center gap-3">
+              <Coins className="h-5 w-5 text-yellow-500" />
+              <div className="text-left">
+                <h3 className="text-base font-semibold">
+                  {t("settings.advanced.pricing.title")}
+                </h3>
+                <p className="text-sm text-muted-foreground font-normal">
+                  {t("settings.advanced.pricing.description")}
+                </p>
+              </div>
+            </div>
+          </AccordionTrigger>
+          <AccordionContent className="px-6 pb-6 pt-4 border-t border-border/50">
+            <PricingConfigPanel />
+          </AccordionContent>
+        </AccordionItem>
+      </Accordion>
     </motion.div>
   );
 }