fix(docker): resolve @cc-platform/server file: dep in container build

Use additional_contexts to copy platform server package into the Docker
build context. Rewrites the file: dependency path and removes the
lockfile so npm install can resolve the local package correctly.
Applied to both production and dev Dockerfiles.

docker-compose.yml

@@ -4,6 +4,8 @@ services:
     build:
       context: ./server
       dockerfile: Dockerfile
+      additional_contexts:
+        platform-server: ../cc-platform-core/server
     container_name: turtle-server
     ports:
       - "4200:3001"  # HTTP API + WebSocket (unified)