refactor: 整合财务系统到主应用并重构后端架构

主要变更:
- 将独立的 web-finance 应用整合到 web-antd 主应用中
- 重命名 backend-mock 为 backend,增强后端功能
- 新增财务模块 API 端点(账户、预算、类别、交易)
- 增强财务仪表板和报表功能
- 添加 SQLite 数据存储支持和财务数据导入脚本
- 优化路由结构,删除冗余的 finance-system 模块

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/backend/api/finance/budgets/[id].delete.ts

@@ -0,0 +1,22 @@
+import { defineEventHandler, getRouterParam } from '#nitro';
+
+import { MOCK_BUDGETS } from '../../../utils/mock-data';
+import { useResponseError, useResponseSuccess } from '../../../utils/response';
+
+export default defineEventHandler(async (event) => {
+  const id = Number(getRouterParam(event, 'id'));
+  const index = MOCK_BUDGETS.findIndex((b) => b.id === id);
+
+  if (index === -1) {
+    return useResponseError('预算不存在', -1);
+  }
+
+  // 软删除
+  MOCK_BUDGETS[index] = {
+    ...MOCK_BUDGETS[index],
+    isDeleted: true,
+    deletedAt: new Date().toISOString(),
+  };
+
+  return useResponseSuccess({ message: '删除成功' });
+});