OptionalfallbackOptionalworkspaceMemento used as the workspace-state fallback. Required when fallbackMode === 'workspace-state'.
OptionalmachineStable identifier mixed into the encryption key. Defaults to empty string. Pass vscode.env.machineId at the call site so secrets cannot be decrypted on a different machine.
OptionalloggerLogger for fallback warnings.
OptionalonCalled once per instance when the fallback is first engaged. Inject the toast at the call site.
Fallback strategy when vscode.SecretStorage throws or is unavailable.