feat(ops): OpenTelemetry + observability profile (#33)

docker-compose.yml

@@ -67,6 +67,8 @@ services:
       Ai__Mode: ${AI_MODE:-Disabled}
       # Points at the compose 'ollama' service when the ai profile is up; harmless otherwise.
       Ai__OllamaBaseUrl: ${OLLAMA_BASE_URL:-http://ollama:11434}
+      # OTLP export activates only when set (e.g. http://lgtm:4317 with the observability profile).
+      OTEL_EXPORTER_OTLP_ENDPOINT: ${OTEL_ENDPOINT:-}
       # Dev mode shows the dev banner and caps the initial sync. Set DEV_MODE=true
       # and MAX_MESSAGES=1000 in deploy/.env to exercise it in this Docker setup.
       App__DevMode: ${DEV_MODE:-false}
@@ -109,6 +111,16 @@ services:
     #           count: all
     #           capabilities: [gpu]
 
+  # Observability (RECOMMENDATIONS #5): all-in-one Grafana+Tempo+Prometheus+Loki.
+  # Enable with: docker compose --profile observability up -d
+  # then set OTEL_ENDPOINT=http://lgtm:4317 in deploy/.env and restart the api.
+  # Grafana UI: http://localhost:3000 (admin/admin on first run).
+  lgtm:
+    image: grafana/otel-lgtm
+    profiles: ["observability"]
+    ports:
+      - "127.0.0.1:3000:3000"
+
   # Optional reverse proxy. Enable with: docker compose --profile proxy up
   nginx:
     image: nginx:alpine