feat(proxy): add global proxy settings support

Add ability to configure a global HTTP/HTTPS proxy for all outbound
requests including provider API calls, speed tests, and stream checks.

src/hooks/useGlobalProxy.ts

@@ -0,0 +1,84 @@
+/**
+ * 全局出站代理 React Hooks
+ *
+ * 提供获取、设置和测试全局代理的 React Query hooks。
+ */
+
+import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
+import { toast } from "sonner";
+import { useTranslation } from "react-i18next";
+import {
+    getGlobalProxyUrl,
+    setGlobalProxyUrl,
+    testProxyUrl,
+    getUpstreamProxyStatus,
+    type ProxyTestResult,
+    type UpstreamProxyStatus,
+} from "@/lib/api/globalProxy";
+
+/**
+ * 获取全局代理 URL
+ */
+export function useGlobalProxyUrl() {
+    return useQuery({
+        queryKey: ["globalProxyUrl"],
+        queryFn: getGlobalProxyUrl,
+    });
+}
+
+/**
+ * 设置全局代理 URL
+ */
+export function useSetGlobalProxyUrl() {
+    const queryClient = useQueryClient();
+    const { t } = useTranslation();
+
+    return useMutation({
+        mutationFn: setGlobalProxyUrl,
+        onSuccess: () => {
+            toast.success(t("settings.globalProxy.saved"));
+            queryClient.invalidateQueries({ queryKey: ["globalProxyUrl"] });
+            queryClient.invalidateQueries({ queryKey: ["upstreamProxyStatus"] });
+        },
+        onError: (error: Error) => {
+            toast.error(
+                t("settings.globalProxy.saveFailed", { error: error.message })
+            );
+        },
+    });
+}
+
+/**
+ * 测试代理连接
+ */
+export function useTestProxy() {
+    const { t } = useTranslation();
+
+    return useMutation({
+        mutationFn: testProxyUrl,
+        onSuccess: (result: ProxyTestResult) => {
+            if (result.success) {
+                toast.success(
+                    t("settings.globalProxy.testSuccess", { latency: result.latencyMs })
+                );
+            } else {
+                toast.error(
+                    t("settings.globalProxy.testFailed", { error: result.error })
+                );
+            }
+        },
+        onError: (error: Error) => {
+            toast.error(error.message);
+        },
+    });
+}
+
+/**
+ * 获取当前出站代理状态
+ */
+export function useUpstreamProxyStatus() {
+    return useQuery<UpstreamProxyStatus>({
+        queryKey: ["upstreamProxyStatus"],
+        queryFn: getUpstreamProxyStatus,
+    });
+}