Merge branch 'js/run-command-close-packs'

The run-command API has been updated so that the callers can easily ask the file descriptors open for packfiles to be closed immediately before spawning commands that may trigger auto-gc. * js/run-command-close-packs: Close object store closer to spawning child processes run_auto_maintenance(): implicitly close the object store run-command: offer to close the object store before running run-command: prettify the `RUN_COMMAND_*` flags pull: release packs before fetching commit-graph: when closing the graph, also release the slab