v1.1.0

Added

• Optional public CoordinatedCredentialStore transaction-lock protocol and
  CredentialCoordinationError for sanitized coordination failures.
• Cross-process OS-backed namespace locks in KeyringCredentialStore, with a
  configurable directory and acquisition timeout, and shared-instance locks in
  MemoryCredentialStore. Credentials and namespace formats remain compatible.
• Public SessionManager.revoke() coordinating broker revocation and local
  deletion; the existing auth CLI now uses it.
• Offline subprocess tests using fake shared keyring storage and mocked OAuth.

Fixed

• Serialize complete lifecycle transactions across cooperating processes, reload
  credentials under the lock, and preserve newer usage/renewal timestamps when
  saving the same credentials. Late usage callbacks cannot restore deleted or
  replaced credentials.
• Wait for cancelled keyring workers before releasing transaction ownership,
  including cancellation of pending tasks during event-loop shutdown.
  Retain credential-free lock files to prevent lock identity replacement races.