aula-15: implementação completa APM (Tempo + OTel + demo app)

Componentes:
- tempo-values.yaml: Grafana Tempo monolithic, 256Mi, 10Gi PVC
- otel-collector-values.yaml: recebe OTLP, exporta traces→Tempo,
  gera span metrics (RED)→Victoria Metrics via spanmetrics connector
- demo-app/: Node.js com rotas /fast (1 query), /slow (N+1, 51 queries),
  /fixed (JOIN), auto-instrumentado com OpenTelemetry
- alerts/latency-alerts.yaml: VMRule com Doherty threshold (p95>400ms)
- setup.sh: instala Tempo, OTel Collector, configura Grafana datasource,
  deploy demo app via ConfigMap (sem Docker build necessário)
- cleanup.sh: remove apenas recursos da aula-15, preserva aula-12

Zero hardcoded hostnames. Tudo via .env e placeholders.

aula-15/otel-collector-values.yaml

@@ -0,0 +1,88 @@
+# OpenTelemetry Collector
+# Chart: open-telemetry/opentelemetry-collector
+# Recebe telemetria das apps e encaminha para Tempo (traces) e Victoria Metrics (metrics)
+
+mode: deployment
+
+replicaCount: 1
+
+image:
+  repository: otel/opentelemetry-collector-contrib
+
+resources:
+  requests:
+    cpu: 50m
+    memory: 128Mi
+  limits:
+    cpu: 200m
+    memory: 256Mi
+
+# Only expose OTLP ports (disable jaeger, zipkin)
+ports:
+  otlp:
+    enabled: true
+    containerPort: 4317
+    servicePort: 4317
+    protocol: TCP
+    appProtocol: grpc
+  otlp-http:
+    enabled: true
+    containerPort: 4318
+    servicePort: 4318
+    protocol: TCP
+  jaeger-compact:
+    enabled: false
+  jaeger-thrift:
+    enabled: false
+  jaeger-grpc:
+    enabled: false
+  zipkin:
+    enabled: false
+
+config:
+  receivers:
+    otlp:
+      protocols:
+        grpc:
+          endpoint: "0.0.0.0:4317"
+        http:
+          endpoint: "0.0.0.0:4318"
+
+  connectors:
+    spanmetrics:
+      histogram:
+        explicit:
+          buckets: [5ms, 10ms, 25ms, 50ms, 100ms, 250ms, 500ms, 1s, 2.5s, 5s, 10s]
+      dimensions:
+        - name: http.method
+        - name: http.route
+        - name: http.status_code
+      namespace: ""
+
+  exporters:
+    otlp/tempo:
+      endpoint: "tempo.monitoring:4317"
+      tls:
+        insecure: true
+    prometheusremotewrite:
+      endpoint: "http://vmsingle-monitoring-victoria-metrics-k8s-stack.monitoring:8429/api/v1/write"
+
+  processors:
+    batch:
+      timeout: 5s
+      send_batch_size: 1024
+    memory_limiter:
+      check_interval: 5s
+      limit_percentage: 80
+      spike_limit_percentage: 25
+
+  service:
+    pipelines:
+      traces:
+        receivers: [otlp]
+        processors: [memory_limiter, batch]
+        exporters: [otlp/tempo, spanmetrics]
+      metrics/spanmetrics:
+        receivers: [spanmetrics]
+        processors: [batch]
+        exporters: [prometheusremotewrite]