* docker: migrate from host to bridge networking
Replace network_mode: host with explicit port mappings and add configuration
volumes for PD, Store, and Server services to support macOS/Windows Docker.
- Remove host network mode from all services
- Add explicit port mappings (8620, 8520, 8080)
- Add configuration directories with volume mounts
- Update healthcheck endpoints
- Add PD peers environment variable
Himanshu Verma