Opening a directory store, read-only or writable, created the .records
folder and its .commit.lock before reading a manifest that might not
exist. Only a write creates them now: PullAll takes the commit lease with
create: false, which opens an existing lock and returns no lease when
there is none (no writer has ever committed there, so there is nothing to
exclude). CommitBatch and PushAll create the folder and lock as before.
Test DirectoryMessagePackBackingStore_Open_CreatesNothing_UntilAWrite:
opening a missing store and a manifest-less .records folder, read-only
and writable, leaves the filesystem unchanged; the first flush creates the
manifest, the lock and one page. With the previous lease code restored
the test fails on the first read-only open.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>