feat: enhance chat service with Redis pub/sub for multi-instance message handling, add instance ID for deduplication

MONITORING.md

@@ -4,12 +4,12 @@ Prometheus + Grafana monitoring for Linear Void.
 
 ## Architecture
 
-```
-┌─────────────┐    ┌──────────────┐    ┌───────────┐
-│  Exporters   │───▶│  Prometheus  │───▶│  Grafana  │
-│  (7 targets) │    │  :9090       │    │  :3001    │
-└─────────────┘    └──────┬───────┘    └───────────┘
-                          │
+```text
+┌──────────────┐     ┌──────────────┐    ┌───────────┐
+│  Exporters   │───> │  Prometheus  │───>│  Grafana  │
+│  (7 targets) │     │  :9090       │    │  :3001    │
+└──────────────┘     └───────┬──────┘    └───────────┘
+                             │
                    alerts.yml (8 rules)
 ```