feat: 初始化微信小程序后端骨架

- NestJS + TypeScript + Prisma + PostgreSQL 工程骨架
- 微信登录安全流程：服务端 code2Session 换 openid 后签发 JWT，
  session_key 缓存于 Redis，不信任前端 openid
- 统一响应/异常处理、JWT 全局鉴权（@Public 豁免）、Swagger 文档
- Prisma 全量核心 schema（用户/分类/商品/设计清单/地址/订单/支付/上传/定制任务）+ seed
- 业务模块空壳（商品/分类/设计清单/地址/订单/支付/上传/BullMQ 队列）
- Docker 多阶段镜像 + 本地/生产 docker-compose
- docs：密钥获取指南、COS SDK 移除记录

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

prisma/schema.prisma

@@ -0,0 +1,220 @@
+// 微信小程序后端 — Prisma schema
+// 数据库：PostgreSQL
+
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "postgresql"
+  url      = env("DATABASE_URL")
+}
+
+// ── 用户 ──────────────────────────────────────────────
+model User {
+  id        String   @id @default(cuid())
+  openid    String   @unique
+  unionid   String?
+  nickname  String?
+  avatar    String?
+  phone     String?
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  orders         Order[]
+  addresses      Address[]
+  designLists    DesignList[]
+  uploads        Upload[]
+  customizations CustomizationTask[]
+
+  @@index([phone])
+}
+
+// ── 商品分类 ──────────────────────────────────────────
+model Category {
+  id       String     @id @default(cuid())
+  name     String
+  parentId String?
+  sort     Int        @default(0)
+  parent   Category?  @relation("CategoryTree", fields: [parentId], references: [id])
+  children Category[] @relation("CategoryTree")
+  products Product[]
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@index([parentId])
+}
+
+// ── 商品 ──────────────────────────────────────────────
+model Product {
+  id          String          @id @default(cuid())
+  name        String
+  categoryId  String?
+  price       Decimal         @db.Decimal(10, 2)
+  images      String[]
+  description String?
+  status      ProductStatus   @default(DRAFT)
+  category    Category?       @relation(fields: [categoryId], references: [id])
+  orderItems  OrderItem[]
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@index([categoryId])
+  @@index([status])
+}
+
+enum ProductStatus {
+  DRAFT
+  ON_SALE
+  OFF_SHELF
+}
+
+// ── 设计清单 / 定制需求 ───────────────────────────────
+model DesignList {
+  id     String           @id @default(cuid())
+  userId String
+  title  String
+  items  Json
+  status DesignListStatus @default(DRAFT)
+  user   User             @relation(fields: [userId], references: [id])
+
+  customizations CustomizationTask[]
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@index([userId])
+}
+
+enum DesignListStatus {
+  DRAFT
+  SUBMITTED
+  PROCESSING
+  DONE
+}
+
+// ── 收货地址 ──────────────────────────────────────────
+model Address {
+  id        String   @id @default(cuid())
+  userId    String
+  name      String
+  phone     String
+  province  String
+  city      String
+  district  String
+  detail    String
+  isDefault Boolean  @default(false)
+  user      User     @relation(fields: [userId], references: [id])
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@index([userId])
+}
+
+// ── 订单 ──────────────────────────────────────────────
+model Order {
+  id             String       @id @default(cuid())
+  orderNo        String       @unique
+  userId         String
+  status         OrderStatus  @default(PENDING)
+  totalAmount    Decimal      @db.Decimal(10, 2)
+  addressSnapshot Json
+  user           User         @relation(fields: [userId], references: [id])
+  items          OrderItem[]
+  payment        Payment?
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@index([userId])
+  @@index([status])
+}
+
+enum OrderStatus {
+  PENDING
+  PAID
+  PROCESSING
+  SHIPPED
+  COMPLETED
+  CANCELLED
+}
+
+model OrderItem {
+  id        String  @id @default(cuid())
+  orderId   String
+  productId String?
+  name      String
+  price     Decimal @db.Decimal(10, 2)
+  quantity  Int
+  order     Order   @relation(fields: [orderId], references: [id], onDelete: Cascade)
+  product   Product? @relation(fields: [productId], references: [id])
+
+  @@index([orderId])
+}
+
+// ── 支付 ──────────────────────────────────────────────
+model Payment {
+  id             String         @id @default(cuid())
+  orderId        String         @unique
+  transactionId  String?
+  provider       PaymentProvider @default(WECHAT)
+  status         PaymentStatus  @default(PENDING)
+  paidAt         DateTime?
+  order          Order          @relation(fields: [orderId], references: [id])
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+}
+
+enum PaymentProvider {
+  WECHAT
+}
+
+enum PaymentStatus {
+  PENDING
+  SUCCESS
+  REFUNDED
+}
+
+// ── 文件上传 ──────────────────────────────────────────
+model Upload {
+  id        String   @id @default(cuid())
+  userId    String
+  cosKey    String
+  url       String
+  mimetype  String?
+  size      Int?
+  user      User     @relation(fields: [userId], references: [id])
+
+  createdAt DateTime @default(now())
+
+  @@index([userId])
+}
+
+// ── 异步定制任务 ──────────────────────────────────────
+model CustomizationTask {
+  id           String                  @id @default(cuid())
+  designListId String?
+  userId       String?
+  status       CustomizationTaskStatus @default(PENDING)
+  resultUrl    String?
+  queueJobId   String?
+  designList   DesignList?             @relation(fields: [designListId], references: [id])
+  user         User?                   @relation(fields: [userId], references: [id])
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@index([designListId])
+  @@index([status])
+}
+
+enum CustomizationTaskStatus {
+  PENDING
+  RUNNING
+  SUCCESS
+  FAILED
+}