Add NATS-over-WebSocket compose for Coolify

Configures a single NATS 2.10 service exposing a WebSocket listener on
:8080 (no_tls; Traefik terminates TLS at nats.volcanic.tes.gd) with
env-driven username/password auth and a persisted JetStream store.

docker-compose.yml

@@ -0,0 +1,24 @@
+services:
+  nats:
+    image: nats:2.10-alpine
+    restart: unless-stopped
+    command: ["-c", "/etc/nats/nats-server.conf"]
+    environment:
+      - SERVICE_FQDN_NATS_8080
+      - NATS_USER=${NATS_USER}
+      - NATS_PASSWORD=${NATS_PASSWORD}
+    volumes:
+      - ./nats-server.conf:/etc/nats/nats-server.conf:ro
+      - nats-data:/data
+    expose:
+      - "4222"
+      - "8080"
+      - "8222"
+    healthcheck:
+      test: ["CMD", "wget", "-qO-", "http://localhost:8222/healthz"]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+
+volumes:
+  nats-data: