Add cron schedules and sync docs

deploy/alertmanager/README.md

@@ -1,9 +1,18 @@
 # Alertmanager
 
-Placeholder for optional Alertmanager integration examples.
+Example Alertmanager configuration for the optional observability profile.
 
-Planned examples:
+`alertmanager.yml` is intentionally safe by default: it routes to a `null`
+receiver, so alerts are grouped but dropped. Before using it outside local
+development, add a real receiver and set `route.receiver` to that receiver.
 
-- receiver config for Monlet-originated alerts;
-- stable label conventions;
-- routing notes for avoiding duplicate notifications.
+Monlet can also send notifications to Alertmanager through the server notifier:
+
+```env
+MONLET_NOTIFIER_ALERTMANAGER_ENABLED=true
+MONLET_NOTIFIER_ALERTMANAGER_URL=http://alertmanager:9093
+```
+
+Keep labels stable and low-cardinality. The example groups by `alertname`,
+`agent_id`, and `check_id`; do not add timestamps, event IDs, or output text to
+Alertmanager labels.

deploy/grafana/README.md

@@ -1,11 +1,20 @@
 # Grafana
 
-Placeholder for Grafana dashboard examples.
+Starter Grafana provisioning for the optional observability profile.
 
-Planned dashboards:
+Files:
 
-- agents alive/stale/dead;
-- check state counts;
-- open incidents;
-- notification outbox state;
-- server ingestion and notifier failures.
+- `provisioning/datasources/prometheus.yml` - adds Prometheus at `http://prometheus:9090`.
+- `provisioning/dashboards/monlet.yml` - loads dashboards from `/var/lib/grafana/dashboards`.
+- `dashboards/monlet-overview.json` - starter dashboard for agent status, open incidents, event ingest rate, and notification rate.
+
+Run it with:
+
+```sh
+cd deploy
+MONLET_AUTH_TOKEN=$(openssl rand -hex 16) docker compose --profile observability up
+```
+
+Grafana is exposed at <http://127.0.0.1:3001>. The local default is
+`admin` / `admin` unless `GF_ADMIN_PASSWORD` is set. Change it before exposing
+Grafana outside local development.

deploy/prometheus/README.md

@@ -1,9 +1,20 @@
 # Prometheus
 
-Placeholder for Prometheus examples.
+Example scrape configuration for the optional observability profile in
+`deploy/docker-compose.yml`.
 
-Planned examples:
+Run it with:
 
-- scrape Monlet agent `/metrics`;
-- scrape Monlet server `/metrics`;
-- sample rules for checks that use `notifications_enabled = false`.
+```sh
+cd deploy
+MONLET_AUTH_TOKEN=$(openssl rand -hex 16) docker compose --profile observability up
+```
+
+The example config scrapes:
+
+- `server:8000/metrics` as `monlet-server`
+- `host.docker.internal:9100/metrics` as `monlet-agent`
+
+Adjust the agent target for your environment. In the showcase stack one demo
+agent exposes metrics on host port `9465`; production agents usually expose
+`metrics.listen` only on the host or a private monitoring network.