feat: add automated backups and Prometheus/Grafana monitoring stack (Steps 17-18)

Backups: pg_dump scripts with daily/weekly rotation and Cloudflare R2 offsite sync.
Monitoring: Prometheus, Grafana, node-exporter, cAdvisor in docker-compose; /metrics
endpoint activated via prometheus_client.

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

app/core/lifespan.py

@@ -16,8 +16,10 @@ from sqlalchemy import text
 
 from middleware.auth import AuthManager
 
+from .config import settings
 from .database import engine
 from .logging import setup_logging
+from .observability import init_observability, shutdown_observability
 
 # Remove this import if not needed: from models.database.base import Base
 
@@ -33,13 +35,22 @@ async def lifespan(app: FastAPI):
     # === STARTUP ===
     app_logger = setup_logging()
     app_logger.info("Starting Orion multi-tenant platform")
+
+    init_observability(
+        enable_metrics=settings.enable_metrics,
+        sentry_dsn=settings.sentry_dsn,
+        environment=settings.sentry_environment,
+        flower_url=settings.flower_url,
+        grafana_url=settings.grafana_url,
+    )
+
     logger.info("[OK] Application startup completed")
 
     yield
 
     # === SHUTDOWN ===
     app_logger.info("Shutting down Orion platform")
-    # Add cleanup tasks here if needed
+    shutdown_observability()
 
 
 # === NEW HELPER FUNCTION ===