feat(msg): graphql subgraph with dataloader for notification/template

- GraphQLModule: Apollo Federation 2 at /graphql

- Notification/NotificationTemplate @key with @ResolveReference

- RouterAuthGuard: validate Router-Authorization header (ADR-036)

- batchFindByIds added to notifications and templates repositories

services/msg/package.json

@@ -34,7 +34,12 @@
     "@opentelemetry/api": "^1.9.0",
     "@opentelemetry/sdk-node": "^0.55.0",
     "@opentelemetry/exporter-trace-otlp-http": "^0.55.0",
-    "@opentelemetry/auto-instrumentations-node": "^0.55.0"
+    "@opentelemetry/auto-instrumentations-node": "^0.55.0",
+    "@apollo/subgraph": "^2.2.3",
+    "@nestjs/apollo": "^12.2.0",
+    "@nestjs/graphql": "^12.2.0",
+    "dataloader": "^2.2.2",
+    "graphql": "^16.9.0"
   },
   "devDependencies": {
     "@nestjs/cli": "^10.4.0",