Overview
useSignOutAll signs out every stored account simultaneously. It sends a sign-out request for each account’s refresh token (best-effort — failures are logged but do not block the operation), then clears all local auth state.
Usage Example
Returns
Async function that signs out all accounts. Sends a server-side sign-out
request for each stored refresh token, clears the accounts map, resets auth
state, and resets the API cache. Throws if the operation fails at the
Redux thunk level.

