feat(teacher-bff): 完整实现 teacher-bff GraphQL 聚合层

包含 clients/graphql/middleware、health probes、shared-ts contracts 等

services/teacher-bff/package.json

@@ -12,15 +12,22 @@
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
+    "@grpc/grpc-js": "^1.12.0",
+    "@grpc/proto-loader": "^0.7.13",
+    "@graphql-tools/schema": "^10.0.6",
+    "@graphql-tools/utils": "^10.5.6",
     "@nestjs/common": "^10.4.0",
     "@nestjs/core": "^10.4.0",
     "@nestjs/platform-express": "^10.4.0",
-    "pino": "^9.4.0",
-    "prom-client": "^15.1.0",
     "@opentelemetry/api": "^1.9.0",
     "@opentelemetry/auto-instrumentations-node": "^0.50.0",
     "@opentelemetry/exporter-trace-otlp-http": "^0.53.0",
     "@opentelemetry/sdk-node": "^0.53.0",
+    "graphql": "^16.9.0",
+    "graphql-yoga": "^5.7.0",
+    "ioredis": "^5.4.1",
+    "pino": "^9.4.0",
+    "prom-client": "^15.1.0",
     "reflect-metadata": "^0.2.2",
     "rxjs": "^7.8.0",
     "zod": "^3.23.0"