v3.13.6 — account-keyed stores: switching accounts no longer shows the previous account's 5h/7d

Fixed

• Switching Claude accounts no longer keeps showing the previous account's
  5h/7d usage. The shared stores (rate_latest.json, rate_projection.json)
  were account-global with no account key, so after /login to a different
  account the old account's reading stayed "plausible" for days and its later
  resets_at won every reconcile merge — the bar stayed pinned to the old
  account's percentages (and its learned →NN% projections) until the old
  window expired. Both stores are now keyed by the logged-in account
  (oauthAccount.accountUuid from ~/.claude.json, memoized on file
  mtime/size — renders normally pay only a stat()): each account gets its own
  rate_latest.<uuid>.json / rate_projection.<uuid>.json, switching back
  restores that account's own data, and when the account can't be detected
  (API-key/headless setups) the legacy unsuffixed paths keep working unchanged.