feat: add OpenTelemetry observability, Faro frontend monitoring, remove legacy Next.js app

- Add OpenTelemetry SDK with tracing, metrics, and OTLP export for API and worker
- Integrate Grafana Faro for frontend real-user monitoring
- Instrument health checks, database, Bull queues, and HTTP exception filter
- Add Grafana dashboard JSON for service overview
- Remove deprecated apps/web-nj (Next.js) — fully replaced by Vite+React frontend
- Update nginx config with OTEL collector proxy
- Minor UI fixes in schema viewer, category components, and subscription flow

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/package.json

@@ -20,6 +20,7 @@
   },
   "dependencies": {
     "@aws-sdk/client-s3": "^3.700.0",
+    "@kubiks/otel-drizzle": "^2.1.0",
     "@nestjs/common": "^10.4.0",
     "@nestjs/config": "^3.3.0",
     "@nestjs/core": "^10.4.0",
@@ -27,10 +28,26 @@
     "@nestjs/schedule": "^4.1.0",
     "@nestjs/swagger": "^8.1.0",
     "@nestjs/throttler": "^6.3.0",
+    "@opentelemetry/api": "^1.9.0",
+    "@opentelemetry/exporter-logs-otlp-http": "^0.212.0",
+    "@opentelemetry/exporter-metrics-otlp-http": "^0.212.0",
+    "@opentelemetry/exporter-trace-otlp-http": "^0.212.0",
+    "@opentelemetry/instrumentation": "^0.212.0",
+    "@opentelemetry/instrumentation-express": "^0.59.0",
+    "@opentelemetry/instrumentation-http": "^0.212.0",
+    "@opentelemetry/instrumentation-ioredis": "^0.59.0",
+    "@opentelemetry/instrumentation-nestjs-core": "^0.57.0",
+    "@opentelemetry/resources": "^2.5.1",
+    "@opentelemetry/sdk-logs": "^0.212.0",
+    "@opentelemetry/sdk-metrics": "^2.5.1",
+    "@opentelemetry/sdk-node": "^0.212.0",
+    "@opentelemetry/sdk-trace-base": "^2.5.1",
+    "@opentelemetry/semantic-conventions": "^1.39.0",
     "@sase/config": "workspace:*",
     "@sase/shared": "workspace:*",
     "better-auth": "^1.2.0",
     "bullmq": "^5.30.0",
+    "bullmq-otel": "^1.2.0",
     "dotenv": "^16.4.0",
     "drizzle-orm": "^0.41.0",
     "helmet": "^8.1.0",