feat(api): 搭建 API 与 Worker 骨架及契约基线

NestJS 11 + Fastify 统一错误体与 trace_id，/health 真实探活 DB/Redis，OpenAPI 3.1 契约含 20 个错误码；shared 包提供错误码、权限点、ULID、分页与通用 schema；worker 完成队列进程骨架。

packages/shared/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "@lingxi/shared",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "main": "./dist/index.cjs",
+  "module": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js",
+      "require": "./dist/index.cjs"
+    }
+  },
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "tsup src/index.ts --format esm,cjs --dts --clean --sourcemap",
+    "dev": "tsup src/index.ts --format esm,cjs --dts --watch",
+    "typecheck": "tsc -p tsconfig.json --noEmit",
+    "test": "vitest run --coverage"
+  },
+  "dependencies": {
+    "zod": "3.25.76"
+  },
+  "devDependencies": {
+    "@vitest/coverage-v8": "3.2.7",
+    "tsup": "8.5.1",
+    "typescript": "5.9.3",
+    "vitest": "3.2.7"
+  }
+}