1190aade82
- Added regression test in `remote-compaction` to verify that concurrent v2 compaction preparation correctly reuses preserved history and avoids redundant re-expansion. - Added mock-backend verification in `session-storage` to ensure that failed atomic title updates do not rollback newer optimistic state. - Updated `sql-session-storage` expectations to account for the preserved fixed-width title slot header in session files. - Expanded `remote-compaction` fetch header validation to include `x-client-request-id` assertion.