feat(config-service): split config-service from iam for plugin/layout config

- new NestJS service on port 3011/gRPC 50059 (ADR-026)
- owns 6 config_ tables (plugin/role-mapping/role-layout/layout-tpl/user-override/outbox)
- GraphQL Federation 2 subgraph with DataLoader + RouterAuthGuard
- gRPC ConfigService + admin REST CRUD + user REST API
- three-layer merge: registry.defaultProps + roleMapping.widget_props + userOverride.props
- Redis cache with 5min TTL
- registered in apollo-router supergraph + docker-compose + port-allocation

Implements M3 of v2.1 migration plan.

services/config-service/package.json

@@ -0,0 +1,51 @@
+{
+  "name": "@edu/config-service",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "nest start --watch",
+    "build": "nest build",
+    "start": "node dist/main.js",
+    "test": "vitest run",
+    "lint": "eslint src",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@apollo/subgraph": "^2.2.3",
+    "@edu/shared-ts": "workspace:*",
+    "@grpc/grpc-js": "^1.12.0",
+    "@grpc/proto-loader": "^0.7.13",
+    "@nestjs/apollo": "^12.2.0",
+    "@nestjs/common": "^10.4.0",
+    "@nestjs/core": "^10.4.0",
+    "@nestjs/graphql": "^12.2.0",
+    "@nestjs/microservices": "^10.4.0",
+    "@nestjs/platform-express": "^10.4.0",
+    "@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",
+    "dataloader": "^2.2.2",
+    "drizzle-orm": "^0.31.0",
+    "graphql": "^16.9.0",
+    "ioredis": "^5.4.0",
+    "kafkajs": "^2.2.4",
+    "mysql2": "^3.11.0",
+    "pino": "^9.4.0",
+    "prom-client": "^15.1.0",
+    "reflect-metadata": "^0.2.2",
+    "rxjs": "^7.8.0",
+    "uuid": "^10.0.0",
+    "zod": "^3.23.0"
+  },
+  "devDependencies": {
+    "@nestjs/cli": "^10.4.0",
+    "@types/express": "^4.17.0",
+    "@types/node": "^22.0.0",
+    "@types/uuid": "^10.0.0",
+    "eslint": "^9.10.0",
+    "typescript": "^5.6.0",
+    "vitest": "^2.1.0"
+  }
+}