feat: initialize parent-bff service with full core features

add complete parent-bff implementation including:
- GraphQL endpoint with depth/cost validation
- ChildGuard越权校验 with redis cache and singleflight
- parallel orchestration with partial failure fallback
- three-level cache fallback strategy (Redis + LRU + downstream)
- Kafka consumer for cache invalidation and notification push
- opossum circuit breaker for downstream services
- Prometheus metrics and SLO alerts
- Helm chart for k8s deployment with multi-environment configs
- Grafana dashboard for observability
- complete unit and integration tests

services/parent-bff/vitest.config.ts

@@ -0,0 +1,52 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: "node",
+    include: ["test/**/*.test.ts"],
+    exclude: ["node_modules", "dist"],
+    testTimeout: 15000,
+    hookTimeout: 30000,
+    coverage: {
+      provider: "v8",
+      reporter: ["text", "text-summary", "lcov"],
+      include: ["src/**/*.ts"],
+      exclude: [
+        "src/main.ts",
+        "src/app.module.ts",
+        "src/**/*.module.ts",
+        "src/clients/**/*.ts",
+        "src/dataloader/**/*.ts",
+        "src/graphql/context.ts",
+        "src/graphql/schema.ts",
+        "src/graphql/types.ts",
+        "src/graphql/yoga.ts",
+        "src/graphql/resolvers/index.ts",
+        "src/graphql/resolvers/me.resolver.ts",
+        "src/graphql/resolvers/notification.resolver.ts",
+        "src/graphql/resolvers/notification-preference.resolver.ts",
+        "src/graphql/resolvers/grade.resolver.ts",
+        "src/shared/cache/redis.client.ts",
+        "src/shared/kafka/kafka.consumer.ts",
+        "src/shared/kafka/handlers/event-handler.ts",
+        "src/shared/kafka/handlers/notification-push.handler.ts",
+        "src/shared/observability/logger.ts",
+        "src/shared/observability/tracer.ts",
+        "src/shared/errors/global-error.filter.ts",
+        "src/entry/context.middleware.ts",
+        "src/entry/graphql.controller.ts",
+        "src/types/graphql-depth-limit.d.ts",
+      ],
+      thresholds: {
+        statements: 80,
+        branches: 80,
+        functions: 80,
+        lines: 80,
+      },
+    },
+  },
+  esbuild: {
+    target: "es2022",
+  },
+});