Add Grafana dashboards for monitoring various services

- Created a new dashboard for NGINX monitoring with panels for status, active connections, request rates, and connection drop ratio.
- Added a Node dashboard to monitor CPU usage, memory usage, disk I/O, and network traffic.
- Introduced a Playout dashboard to track service status, mode, FFmpeg restarts, and scrape duration.
- Implemented a PostgreSQL dashboard featuring active connections, database size, transaction rates, and cache hit ratio.
- Developed a Prometheus dashboard to visualize scrape duration, targets status, and rule evaluation metrics.
- Established a Redis dashboard to monitor connected clients, memory usage, command latency, and keyspace statistics.

docs/infrastructure/monitoring/prometheus_curl.md

@@ -3,69 +3,60 @@
 Here are ready‑to‑run **cURL** commands you can use to query each Prometheus scrape target and list the metric names they expose.  
 The Prometheus HTTP API endpoint `http://localhost:9090/api/v1/label/__name__/values` returns all metric names currently known for the target’s job/instance.
 
----
-
 ## 1. Chat (`http://chat:3000/metrics`)
 
+[Browse `chat`](http://192.168.88.40:9090/api/v1/label/__name__/values?match[]={job=%22chat%22})
+
 ```bash
 curl -s 'http://localhost:9090/api/v1/label/__name__/values?match[]={job="chat",instance="chat:3000"}' | jq .
 ```
 
+see [Prometheus Results](./prometheus_results.md#chat-metrics) for full output of all 20+ metric names exposed by the Chat service.
+
 ## 2. NGINX exporter (`http://nginx-exporter:9113/metrics`)
 
 ```bash
 curl -s 'http://localhost:9090/api/v1/label/__name__/values?match[]={job="nginx",instance="nginx-exporter:9113"}' | jq .
 ```
 
+see [Prometheus Results](./prometheus_results.md#nginx-metrics) for full output of all 40+ metric names exposed by the NGINX exporter.
+
 ## 3. Node exporter (`http://node-exporter:9100/metrics`)
 
 ```bash
 curl -s 'http://localhost:9090/api/v1/label/__name__/values?match[]={job="node",instance="node-exporter:9100"}' | jq .
 ```
 
+see [Prometheus Results](./prometheus_results.md#node-metrics) for full output of all 200+ metric names exposed by the Node exporter.
+
 ## 4. Playout (`http://playout:8081/metrics`)
 
 ```bash
 curl -s 'http://localhost:9090/api/v1/label/__name__/values?match[]={job="playout",instance="playout:8081"}' | jq .
 ```
 
+see [Prometheus Results](./prometheus_results.md#playout-metrics) for full output of all 10+ metric names exposed by the Playout service.
+
 ## 5. Postgres exporter (`http://postgres-exporter:9187/metrics`)
 
 ```bash
 curl -s 'http://localhost:9090/api/v1/label/__name__/values?match[]={job="postgres",instance="postgres-exporter:9187"}' | jq .
 ```
 
+see [Prometheus Results](./prometheus_results.md#postgres-metrics) for full output of all 100+ metric names exposed by the Postgres exporter.
+
 ## 6. Prometheus itself (`http://prometheus:9090/metrics`)
 
 ```bash
 curl -s 'http://localhost:9090/api/v1/label/__name__/values?match[]={job="prometheus",instance="prometheus:9090"}' | jq .
 ```
 
+see [Prometheus Results](./prometheus_results.md#prometheus-metrics) for full output of all 100+ metric names exposed by Prometheus itself.
+
 ## 7. Redis exporter (`http://redis-exporter:9121/metrics`)
 
 ```bash
 curl -s 'http://localhost:9090/api/v1/label/__name__/values?match[]={job="redis",instance="redis-exporter:9121"}' | jq .
 ```
 
----
-
-### How it works
-
-- `http://localhost:9090` – address of your Prometheus server.
-- `/api/v1/label/__name__/values` – API call that lists _all_ metric names (`__name__` label) known to Prometheus.
-- `match[]` – a selector that restricts the result to the specific `job` and `instance` you care about.
-- `-s` – silent mode (no progress meter).
-- `| jq .` – pretty‑prints the JSON response (optional but handy).
-
-Running any of these commands will output a JSON array like:
-
-```json
-[
-  "up",
-  "process_cpu_seconds_total",
-  "http_requests_total",
-  ...
-]
-```
-
-which is the full set of metrics currently being scraped from that target. Adjust the Prometheus host/port if it differs from `http://localhost:9090`.
+see [Prometheus Results](./prometheus_results.md#redis-metrics) for full output of all 100+ metric names exposed by the Redis exporter.