feat: 添加代理配置功能，包括主机、端口、用户名和密码设置

src/routes/settings/proxy/+page.svelte

@@ -0,0 +1,19 @@
+<script lang="ts">
+import EnableProxy from './EnableProxy.svelte';
+import ProtocolSelect from './ProtocolSelect.svelte';
+import ProxyHost from './ProxyHost.svelte';
+import ProxyPassword from './ProxyPassword.svelte';
+import ProxyPort from './ProxyPort.svelte';
+import ProxyUsername from './ProxyUsername.svelte';
+
+let enabledProxy = $state<boolean>(false);
+</script>
+
+<section class="px-2 py-4 flex flex-col gap-2">
+  <ProtocolSelect />
+  <ProxyHost />
+  <ProxyPort />
+  <ProxyUsername />
+  <ProxyPassword />
+  <EnableProxy />
+</section>