v3.52.2

• Prevent a newly observed session replaying an older quota snapshot from
  lowering the shared account reading after its confirmation grace expires.
  For example, a frozen 91% weekly reading no longer replaces a recorded 100%.
• Require a subsequent change in that window's raw quota signature, newer
  than the shared value, before accepting a downward recalibration.
  A change in 5h usage cannot make an unchanged weekly snapshot fresh.
  Genuine recalibrations still use the existing grace period; unchanged
  snapshots remain unable to confirm or overwrite quota after their idle TTL.
• Cover late-session replays, delayed recalibrations, and concurrent writes
  from separate processes with regression tests.