Codex's converge pass on PR B found a cross-cwd adoption hole: the coordinator
calls loadLive(id, session.header.cwd) for HMR live-adoption, but JSONL's
loadLive delegated to findLog(id, cwd) which, for cwd === undefined, scanned
ALL cwd buckets. So a live NO-CWD session could adopt a same-id log from a real
cwd bucket, ending with a live cwd: undefined but a persisted meta.cwd: '/w'.
loadLive must treat `undefined` as the DEFINITE no-cwd bucket, not "unknown":
it now goes straight to logPath(cwd, id) (which maps undefined -> _no-cwd),
never the all-buckets scan. loadStored/deleteStored keep the any-cwd scan
(resume/removal identify by id alone), so findLog is now a pure scan-all and
loses its dead cwd-direct branch.
The coordinator's has() relied on loadLive(id, undefined) meaning "any scope"
for an untracked id — fixed to use loadStored for the untracked (unknown-cwd)
case and loadLive only for a tracked session's known cwd.
Adds a regression test: a no-cwd live session reusing an id persisted in a real
cwd bucket no longer cross-cwd-adopts — it falls through to createCore's
any-cwd collision probe and REJECTS, leaving the original log untouched. Also
fixes the README to say `tornMarker !== undefined` (a marker may be falsy, 0).
Tianyi Cui
3d67a98291