chore: 统一代码格式并配置开发工具

- 添加 ESLint 和 Prettier 配置以统一代码风格
- 配置项目级 TypeScript 设置
- 更新前后端依赖版本
- 修复代码格式问题（引号、分号、尾随逗号等）
- 优化文件结构和导入路径

backend/src/posts.ts

@@ -1,38 +1,42 @@
-import { Elysia, t } from 'elysia';
-import { prisma } from './prisma';
+import { Elysia, t } from 'elysia'
+import { prisma } from './prisma'
 
 export const posts = new Elysia({ prefix: '/posts' })
   .get('/', async () => {
     return await prisma.post.findMany({
       include: { user: true },
-      orderBy: { createdAt: 'desc' }
-    });
+      orderBy: { createdAt: 'desc' },
+    })
   })
   .get('/:id', async ({ params: { id } }) => {
     return await prisma.post.findUnique({
       where: { id },
-      include: { 
-        user: true, 
+      include: {
+        user: true,
         comments: {
           include: {
-            user: true
+            user: true,
           },
           orderBy: {
-            createdAt: 'desc'
-          }
-        } 
-      }
-    });
-  })
-  .post('/', async ({ body }) => {
-    return await prisma.post.create({
-      data: body
-    });
-  }, {
-    body: t.Object({
-      title: t.String(),
-      content: t.String(),
-      userId: t.String(),
-      published: t.Optional(t.Boolean())
+            createdAt: 'desc',
+          },
+        },
+      },
     })
-  });
+  })
+  .post(
+    '/',
+    async ({ body }) => {
+      return await prisma.post.create({
+        data: body,
+      })
+    },
+    {
+      body: t.Object({
+        title: t.String(),
+        content: t.String(),
+        userId: t.String(),
+        published: t.Optional(t.Boolean()),
+      }),
+    },
+  )