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/ProxyPassword.svelte

@@ -0,0 +1,67 @@
+<script lang="ts">
+import { getProxyConfig, loadAppConfig, updateProxyConfig } from '$lib/utils/app-config';
+import {
+  createDebouncedTrigger,
+  createSaveFeedbackController,
+  type SaveFeedbackState,
+} from '$lib/utils/form-save';
+import { onDestroy, onMount } from 'svelte';
+
+let proxyPassword = $state<string>('');
+let saveFeedback = $state<SaveFeedbackState>('idle');
+
+const feedback = createSaveFeedbackController((state) => {
+  saveFeedback = state;
+});
+
+onMount(async () => {
+  try {
+    const config = await loadAppConfig();
+    proxyPassword = getProxyConfig(config).password ?? '';
+  } catch (error) {
+    console.error('Failed to load proxy password:', error);
+  }
+});
+
+onDestroy(() => {
+  saveLater.cancel();
+  feedback.dispose();
+});
+
+async function saveProxyPassword(value: string) {
+  const nextPassword = value.trim();
+
+  try {
+    await updateProxyConfig((current) => ({
+      ...current,
+      password: nextPassword || null,
+    }));
+    feedback.markUpdated();
+  } catch (error) {
+    console.error('Failed to save proxy password:', error);
+    feedback.markNotUpdated();
+  }
+}
+
+const saveLater = createDebouncedTrigger(() => {
+  void saveProxyPassword(proxyPassword);
+}, 800);
+
+function savePasswordDelayed() {
+  saveLater.trigger();
+}
+</script>
+
+<label
+  class={[
+    'input w-fit in-focus-within:outline-none transition-colors duration-300 ease-out',
+    saveFeedback === 'updated' && 'border-green-500',
+    saveFeedback === 'not-updated' && 'border-red-500',
+  ]}>
+  <span class="label min-w-[10em]">Password</span>
+  <input
+    type="password"
+    bind:value={proxyPassword}
+    oninput={savePasswordDelayed}
+    class="min-w-[20em] focus:outline-none" />
+</label>