Remove keys volume mount and add install script

- Remove /etc/provisioning/keys mount (ephemeral keys are in-memory now)
- Remove /etc/provisioning VOLUME from Dockerfile
- Add deploy/install.sh that creates config files before docker compose up,
  preventing Docker from creating directories in place of missing bind mounts
- Update README with install script usage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -7,7 +7,6 @@ services:
     volumes:
       - ./provisioning.yaml:/etc/provisioning/provisioning.yaml:ro
       - ./server-types.yaml:/etc/provisioning/server-types.yaml:ro
-      - ./keys:/etc/provisioning/keys:ro
       - data:/data
     command: ["-config", "/etc/provisioning/provisioning.yaml"]
     cap_add: