feat(telemetry): add OpenTelemetry tracing with optional OTLP export to Tempo

docker/tempo/docker-compose.yaml

@@ -0,0 +1,27 @@
+services:
+  tempo:
+    image: grafana/tempo:latest
+    command: ["-config.file=/etc/tempo.yaml"]
+    volumes:
+      - ./tempo.yaml:/etc/tempo.yaml:ro
+      - tempo-data:/var/tempo
+    ports:
+      - "4317:4317"   # OTLP gRPC
+      - "4318:4318"   # OTLP HTTP
+      - "3200:3200"   # Tempo query API
+
+  grafana:
+    image: grafana/grafana:latest
+    environment:
+      - GF_AUTH_ANONYMOUS_ENABLED=true
+      - GF_AUTH_ANONYMOUS_ORG_ROLE=Admin
+      - GF_AUTH_DISABLE_LOGIN_FORM=true
+    volumes:
+      - ./grafana-datasources.yaml:/etc/grafana/provisioning/datasources/datasources.yaml:ro
+    ports:
+      - "9715:3000"   # Grafana UI (project port convention)
+    depends_on:
+      - tempo
+
+volumes:
+  tempo-data: