feat(demo): add read-only demo dockerfile and nginx api mocking.

docker-compose.demo.yml

@@ -0,0 +1,29 @@
+services:
+  meshchatx-demo:
+    build:
+      context: .
+      dockerfile: Dockerfile.demo
+    image: ${MESHCHAT_DEMO_IMAGE:-reticulum-meshchatx-demo:local}
+    container_name: reticulum-meshchatx-demo
+    restart: unless-stopped
+    ports:
+      - "8080:8080"
+    
+    # Security Hardening
+    security_opt:
+      - no-new-privileges:true
+    read_only: true
+    tmpfs:
+      - /tmp:mode=1777
+      - /var/cache/nginx:mode=1777
+      - /var/run:mode=1777
+    cap_drop:
+      - ALL
+    
+    # Resource Limits
+    deploy:
+      resources:
+        limits:
+          memory: 128M
+        reservations:
+          memory: 64M