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

apps/api/src/modules/platform/health/health.service.ts

@@ -0,0 +1,94 @@
+import { ErrorCode, nowIso } from '@lingxi/shared';
+import { Inject, Injectable } from '@nestjs/common';
+
+import { AppException } from '../../../common/errors/app-exception';
+import { APP_CONFIG } from '../../../config/config.module';
+import type { AppConfig } from '../../../config/env';
+import type { PrismaService } from '../../../infra/prisma/prisma.service';
+import type { RedisService } from '../../../infra/redis/redis.service';
+import { PRISMA } from '../../../infra/tokens';
+import { REDIS } from '../../../infra/tokens';
+import type { ComponentHealth, HealthReport } from './health.types';
+
+const API_VERSION = '0.1.0';
+const CHECK_TIMEOUT_MS = 2000;
+
+function withTimeout<T>(task: Promise<T>, timeoutMs: number): Promise<T> {
+  return new Promise<T>((resolve, reject) => {
+    const timer = setTimeout(() => {
+      reject(new Error(`检查超时（${String(timeoutMs)}ms）`));
+    }, timeoutMs);
+    void task.then(
+      (value) => {
+        clearTimeout(timer);
+        resolve(value);
+      },
+      (error: unknown) => {
+        clearTimeout(timer);
+        reject(error instanceof Error ? error : new Error(String(error)));
+      },
+    );
+  });
+}
+
+/**
+ * 健康检查：真实检查数据库（SELECT 1）与 Redis（PING），不只看端口（技术架构 §4.1.1）。
+ * 任一依赖不可用时返回 503 + 统一错误体，details 里带完整检查快照。
+ */
+@Injectable()
+export class HealthService {
+  constructor(
+    @Inject(PRISMA) private readonly prisma: PrismaService,
+    @Inject(REDIS) private readonly redis: RedisService,
+    @Inject(APP_CONFIG) private readonly config: AppConfig,
+  ) {}
+
+  async check(): Promise<HealthReport> {
+    const [database, redis] = await Promise.all([this.checkDatabase(), this.checkRedis()]);
+    const report: HealthReport = {
+      status: database.status === 'up' && redis.status === 'up' ? 'ok' : 'degraded',
+      env: this.config.nodeEnv,
+      version: API_VERSION,
+      uptimeSeconds: Math.round(process.uptime()),
+      checks: { database, redis },
+      timestamp: nowIso(),
+    };
+
+    if (report.status === 'degraded') {
+      throw new AppException({
+        code: ErrorCode.DEPENDENCY_UNAVAILABLE,
+        message: '依赖服务不可用',
+        details: report.checks,
+      });
+    }
+    return report;
+  }
+
+  private async checkDatabase(): Promise<ComponentHealth> {
+    const startedAt = Date.now();
+    try {
+      await withTimeout(this.prisma.$queryRaw`SELECT 1`, CHECK_TIMEOUT_MS);
+      return { status: 'up', latencyMs: Date.now() - startedAt };
+    } catch (error) {
+      return {
+        status: 'down',
+        latencyMs: Date.now() - startedAt,
+        error: error instanceof Error ? error.message : '未知错误',
+      };
+    }
+  }
+
+  private async checkRedis(): Promise<ComponentHealth> {
+    const startedAt = Date.now();
+    try {
+      await withTimeout(this.redis.ping(), CHECK_TIMEOUT_MS);
+      return { status: 'up', latencyMs: Date.now() - startedAt };
+    } catch (error) {
+      return {
+        status: 'down',
+        latencyMs: Date.now() - startedAt,
+        error: error instanceof Error ? error.message : '未知错误',
+      };
+    }
+  }
+}