feat: implement dynamic changelog loading from API

- Add GET /api/changelog endpoint to fetch changelog from CHANGELOG.md
- Create service/changelog.go to parse CHANGELOG.md markdown file
- Add handler/changelog.go to handle changelog requests
- Update ChangelogDrawer component to fetch from API instead of hardcoded data
- Export apiFetch from lib/api.ts for public use
- Add changelog parser tests with 14 version entries verified

web/src/lib/api.ts

@@ -5,7 +5,7 @@ import type { UIBill } from '$lib/models/bill';
 // API 配置 - 使用相对路径，由 SvelteKit 代理到后端
 const API_BASE = '';
 
-async function apiFetch(input: RequestInfo | URL, init: RequestInit = {}) {
+export async function apiFetch(input: RequestInfo | URL, init: RequestInit = {}) {
   const headers = new Headers(init.headers);
 
   if (browser) {

web/src/lib/components/ChangelogDrawer.svelte

@@ -3,77 +3,48 @@
 	import { Button } from '$lib/components/ui/button';
 	import Calendar from '@lucide/svelte/icons/calendar';
 	import Tag from '@lucide/svelte/icons/tag';
+	import { onMount } from 'svelte';
+	import { apiFetch } from '$lib/api';
 
 	let { open = $bindable(false) } = $props();
 
-	// Changelog 内容（从 CHANGELOG.md 解析或硬编码）
-	const changelog = [
-		{
-			version: '1.3.1',
-			date: '2026-01-26',
-			changes: {
-				优化: [
-					'版本号显示优化 - 侧边栏版本号按钮样式改进',
-					'移至次级导航区域，与其他菜单项样式一致',
-					'更新日志改用 Sheet 组件（右侧滑出），替代底部 Drawer',
-					'统一暗色主题下的视觉效果'
-				]
+	interface ChangelogEntry {
+		version: string;
+		date: string;
+		changes: Record<string, string[]>;
+	}
+
+	let changelog = $state<ChangelogEntry[]>([]);
+	let isLoading = $state(false);
+	let error = $state<string | null>(null);
+
+	// 获取更新日志
+	async function fetchChangelog() {
+		isLoading = true;
+		error = null;
+		try {
+			const response = await apiFetch('/api/changelog');
+			if (!response.ok) {
+				throw new Error(`HTTP ${response.status}`);
 			}
-		},
-		{
-			version: '1.3.0',
-			date: '2026-01-26',
-			changes: {
-				新增: [
-					'京东账单支持 - 支持京东白条账单上传和清洗',
-					'自动识别京东账单类型（交易流水 ZIP）',
-					'解析京东白条账单 CSV 格式（含还款日期信息）',
-					'京东专属分类映射配置',
-					'支持京东外卖、京东平台商户等商户识别',
-					'上传页面和账单列表页面添加"京东"选项'
-				],
-				优化: [
-					'京东订单智能去重 - 上传京东账单时自动软删除其他来源中的京东订单',
-					'分类推断复核等级优化 - 京东账单引入 LOW 复核等级',
-					'京东平台商户关键词扩展'
-				],
-				技术改进: [
-					'新增京东账单清理器',
-					'新增京东专属配置',
-					'后端新增软删除接口',
-					'新增单元测试（11 个测试用例）'
-				]
-			}
-		},
-		{
-			version: '1.2.1',
-			date: '2026-01-23',
-			changes: {
-				优化: [
-					'智能复核快捷确认 - 在复核列表每行添加快捷确认按钮',
-					'无需打开详情页面即可确认分类正确',
-					'自动更新统计数据',
-					'提升复核效率，支持快速批量确认'
-				],
-				文档: ['AGENTS.md 更新 - 精简为 150 行，专为 AI 编程助手设计']
-			}
-		},
-		{
-			version: '1.2.0',
-			date: '2026-01-25',
-			changes: {
-				新增: [
-					'账单删除功能 - 支持在账单详情抽屉中删除账单（软删除）',
-					'删除按钮带二次确认，防止误操作',
-					'已删除的账单在所有查询中自动过滤'
-				],
-				技术改进: [
-					'后端 MongoDB 查询方法添加软删除过滤',
-					'新增 DELETE /api/bills/:id 接口'
-				]
+			const data = await response.json();
+			if (data.result && Array.isArray(data.data)) {
+				changelog = data.data;
+			} else {
+				throw new Error('Invalid response format');
 			}
+		} catch (err) {
+			error = err instanceof Error ? err.message : 'Failed to fetch changelog';
+			console.error('Failed to fetch changelog:', err);
+		} finally {
+			isLoading = false;
 		}
-	];
+	}
+
+	// 组件挂载时获取数据
+	onMount(() => {
+		fetchChangelog();
+	});
 </script>
 
 <Sheet.Root bind:open>
@@ -85,7 +56,20 @@
 			</Sheet.Description>
 		</Sheet.Header>
 
-		<div class="flex-1 overflow-y-auto py-6">
+	<div class="flex-1 overflow-y-auto py-6">
+		{#if isLoading}
+			<div class="flex items-center justify-center py-8">
+				<div class="text-muted-foreground">加载中...</div>
+			</div>
+		{:else if error}
+			<div class="flex items-center justify-center py-8">
+				<div class="text-destructive text-sm">{error}</div>
+			</div>
+		{:else if changelog.length === 0}
+			<div class="flex items-center justify-center py-8">
+				<div class="text-muted-foreground">暂无更新日志</div>
+			</div>
+		{:else}
 			<div class="space-y-8">
 				{#each changelog as release}
 					<div class="space-y-3">
@@ -120,7 +104,8 @@
 					</div>
 				{/each}
 			</div>
-		</div>
+		{/if}
+	</div>
 
 		<Sheet.Footer class="border-t pt-4">
 			<Button variant="outline" onclick={() => (open = false)} class="w-full">关闭</Button>