feat(a0): 完成工程骨架与契约基线

- 建立 pnpm workspace + Turborepo 单仓、ESLint 9/Prettier/commitlint/husky 门禁
- NestJS + Fastify API：统一错误体、trace_id、Zod 管道、/health 真实依赖探活、OpenAPI 3.1 契约
- Prisma 基线：outbox_events/idempotency_keys/system_configs 与首版迁移、幂等种子
- shared 契约包：错误码、权限点、ULID、游标分页、命名/时间工具
- ui 包与 Web 壳层：Semi + Remix 图标统一出口、Cloud Blue 视觉、登录/工作台/错误页
- worker 骨架、Playwright 冒烟、Gitea CI、OpenAPI 快照与 oasdiff 回退脚本
- 补充 A0 实施报告与本地开发说明

turbo.json

@@ -0,0 +1,25 @@
+{
+  "$schema": "https://turbo.build/schema.json",
+  "ui": "stream",
+  "tasks": {
+    "build": {
+      "dependsOn": ["^build"],
+      "outputs": ["dist/**"]
+    },
+    "dev": {
+      "cache": false,
+      "persistent": true
+    },
+    "typecheck": {
+      "dependsOn": ["^build"]
+    },
+    "test": {
+      "dependsOn": ["^build"],
+      "outputs": ["coverage/**"]
+    },
+    "test:int": {
+      "dependsOn": ["^build"],
+      "cache": false
+    }
+  }
+}