fix(deploy): restore context: .. in compose (relative to deploy/ file); remove invalid || from backend/Dockerfile; prune backend from .dockerignore so COPY succeeds

deploy/docker-compose.yml

@@ -14,7 +14,7 @@
 services:
   frontend:
     build:
-      context: .
+      context: ..
       dockerfile: frontend/Dockerfile
     ports: ["127.0.0.1:${FRONTEND_PORT:-18080}:80"]
     depends_on: [fastapi]
@@ -22,7 +22,7 @@ services:
 
   fastapi:
     build:
-      context: .
+      context: ..
       dockerfile: backend/Dockerfile
     env_file:
       - .env