feat: Prisma 用户落库、迁移与启动环境加载

- Prisma 7 + adapter-pg；prisma.config 与 users 初始迁移\n- AppModule 挂载 PrismaModule；PrismaService 仅依赖 DATABASE_URL\n- main 入口 dotenv/config，避免 Prisma 早于 Config 读 env\n- 短信登录 upsert User；默认昵称 Chat+手机号后四位\n- README / project-solution：目录、迁移规范、用户 avatar_url 说明\n- 依赖：dotenv、@prisma/adapter-pg、pg

Made-with: Cursor

package.json

@@ -12,7 +12,8 @@
     "start": "node dist/main.js",
     "start:dev": "tsx watch src/main.ts",
     "start:debug": "node --inspect=0.0.0.0:9229 dist/main.js",
-    "lint": "eslint \"src/**/*.ts\""
+    "lint": "eslint \"src/**/*.ts\"",
+    "postinstall": "prisma generate"
   },
   "dependencies": {
     "@fastify/static": "^9.1.1",
@@ -25,15 +26,18 @@
     "@nestjs/schedule": "^6.1.3",
     "@nestjs/swagger": "^11.3.0",
     "@nestjs/throttler": "^6.5.0",
+    "@prisma/adapter-pg": "^7.7.0",
     "@prisma/client": "^7.7.0",
     "class-transformer": "^0.5.1",
     "class-validator": "^0.15.1",
     "dayjs": "^1.11.20",
+    "dotenv": "^17.4.2",
     "helmet": "^8.1.0",
     "ioredis": "^5.10.1",
     "nestjs-pino": "^4.6.1",
     "passport": "^0.7.0",
     "passport-jwt": "^4.0.1",
+    "pg": "^8.20.0",
     "pino-http": "^11.0.0",
     "reflect-metadata": "^0.2.2",
     "rxjs": "^7.8.2",