fix: Remove invalid Docker build targets from docker-compose-deploy.yml

🔧 Docker Compose Fix

## Issue Fixed:
- Docker build failing with 'failed to reach build target production'
- docker-compose-deploy.yml referencing non-existent multi-stage targets

## Solution:
- Removed 'target: production' from nodebook-p2p service
- Removed 'target: production' from signaling-server service
- Simplified to use single-stage Dockerfile.prod

## Key Changes:
- nodebook-p2p: Removed target specification
- signaling-server: Removed target specification
- Both services now use simplified Dockerfile.prod

This fixes the production deployment build error where Docker
was trying to reach non-existent build targets.

Author: gnowgi

docker-compose-deploy.yml

@@ -29,7 +29,6 @@ services:
     build:
       context: ./nodebook-base
       dockerfile: Dockerfile.prod
-      target: production
     container_name: nodebook-p2p-prod
     # No external ports - only accessible via nginx proxy
     volumes:
@@ -76,7 +75,6 @@ services:
     build:
       context: ./nodebook-base
       dockerfile: Dockerfile.prod
-      target: production
     container_name: nodebook-signaling-server-prod
     # No external ports - only accessible via nginx proxy
     volumes: