feat: Initial Docker Compose setup for conversation layer

Adds a docker-compose.yml to manage the OpenWA, Chat UI, and WhatsApp Router services.

Includes:
- Dockerfile and basic Node.js skeleton for Chat UI.
- Dockerfile and basic Node.js skeleton for WhatsApp Router.
- docker-compose.yml defining the three services, including:
    - Placeholder for OpenWA image (you must configure this).
    - Build contexts for UI and router.
    - Port mappings.
    - Environment variable examples.
    - Volume for OpenWA session persistence.
- Updated README.md with detailed setup, configuration, and usage instructions.

docker-compose.yml

@@ -0,0 +1,67 @@
+version: '3.8'
+
+services:
+  openwa:
+    # IMPORTANT: Replace with your specific OpenWA image if different.
+    # This is a commonly used one, but your setup might require another.
+    image: devlikeapro/open-wa-api:latest
+    ports:
+      # Default port for OpenWA API is often 8080. Adjust if your image uses a different one.
+      - "8080:8080"
+      # Port for the webhook if OpenWA serves it directly.
+      # This might also be configured via environment variables for OpenWA.
+      - "3000:3000" # Assuming OpenWA's webhook might be on 3000, adjust as needed
+    environment:
+      # Add any necessary environment variables for OpenWA here
+      # For example:
+      # - WEBHOOK_URL=http://whatsapp-router:3001/webhook
+      # The actual variable names will depend on the OpenWA image being used.
+      - SERVER_PORT=8080 # Example, may not be needed if image defaults correctly
+    volumes:
+      # Persist session data for OpenWA to avoid re-scanning QR code on restart
+      - openwa_data:/app/session
+    # networks:
+    #  - conversation_net
+
+  chat-ui:
+    build:
+      context: ./chat-ui
+      dockerfile: Dockerfile
+    ports:
+      - "3002:3000" # Expose Chat UI on host port 3002, container port 3000
+    environment:
+      # Example: Endpoint for the LLM agent
+      # - LLM_AGENT_URL=http://your-llm-agent-service/api
+      - NODE_ENV=development
+    # depends_on:
+    #  - openwa # If Chat UI needs to directly interact with OpenWA
+    # networks:
+    #  - conversation_net
+
+  whatsapp-router:
+    build:
+      context: ./whatsapp-router
+      dockerfile: Dockerfile
+    ports:
+      - "3001:3001" # Expose WhatsApp Router on host port 3001, container port 3001
+    environment:
+      # URL for OpenWA API
+      - OPENWA_API_URL=http://openwa:8080
+      # URL where OpenWA should send webhook events
+      # This should match what OpenWA is configured to call
+      - OPENWA_WEBHOOK_TARGET=http://whatsapp-router:3001/webhook
+      # Example: Endpoint for the LLM agent (if router talks to it)
+      # - LLM_AGENT_URL=http://your-llm-agent-service/api
+      - NODE_ENV=development
+    depends_on:
+      - openwa # Router needs OpenWA to be up
+    # networks:
+    #  - conversation_net
+
+volumes:
+  openwa_data: # Named volume for OpenWA session data
+
+# Optional: Define a shared network
+# networks:
+#  conversation_net:
+#    driver: bridge