Function update_object_meta 

pub(crate) fn update_object_meta(
    store: &Store,
    oref_str: &str,
    meta_update: &HashMap<String, Value>,
) -> Result<(), String>

Update object meta by oref string. Merges meta into existing object.

The whole read-merge-write round trip runs inside ONE Store::with_tx critical section (a single acquisition of the store’s connection Mutex, wrapping a real SQLite transaction) instead of two separate must_get/update calls. This closes a lost-update race: two call sites can legitimately fire on the SAME block within milliseconds of each other — e.g. persist_session_id (clearing a stale --resume id) and clear_active_pid both run from independent async tasks on a persistent controller’s process exit. Each used to read a pre-write snapshot of the block’s entire meta map, merge in its own single key, and write the entire merged map back — so whichever of the two won the race to write LAST silently reverted the other’s change (every key it didn’t itself touch reverts to whatever it read, which may already be stale). with_tx holds the one connection lock across the full read+merge+write, so no other Store::* call for ANY object can interleave inside it — the two writers now strictly serialize instead of racing, and each one’s merge is always built from the other’s already-committed result. See REPORT_LOGIN_PERSIST_FAILURE_AND_STUCK_WORKING_2026_07_27.md.