fix: Docker Compose configuration fixes

- Fix frontend Dockerfile reference (Dockerfile not Dockerfile.frontend)
- Remove obsolete 'version' attribute from docker-compose.yml
- Add --legacy-peer-deps to npm ci in frontend Dockerfile

Docker build now works correctly.

docker-compose.yml

@@ -1,5 +1,3 @@
-version: '3.8'
-
 services:
   # PostgreSQL Database
   postgres:
@@ -146,7 +144,7 @@ services:
   frontend:
     build:
       context: ./frontend
-      dockerfile: Dockerfile.frontend
+      dockerfile: Dockerfile
     container_name: mockupaws-frontend
     restart: unless-stopped
     environment: