Replace the legacy top-level management key with a unified paths-based
model. Each domain now contains a paths map where each entry defines its
own backend, auth, headers, and flags (is_management, is_websocket).
- Add _migrate_config() to auto-migrate legacy formats on first load
- Remove set_management_proxy() and POST_NGINX_MANAGEMENT endpoint
- Update server_block.conf template to iterate paths with per-location auth
- Update daemon handler, API blueprint, state collector, and install script
- Add server config generation tests for paths, WebSocket, auth inheritance
- Update frontend proxy page to display per-path rows with flags
mteehan
835326311b