feat(drive): remove create_home_folder

remove create_home_folder() & ensure_home_folder()

    now: on_user_created() and on_user_login both() call provision_if_needed()
    which calls **create_personal_drive_atomic()**

    add a helper to find Personal drive for a user and also it's root directorry

src/application/ports/user_lifecycle.rs

@@ -127,7 +127,7 @@ pub enum LogoutReason {
 
 /// How aggressively `on_user_deleted` cleanup should run. Today both
 /// variants are equivalent (only `AuditLifecycleHook` exists, and it logs
-/// regardless). The split exists so PR 4's `HomeFolderLifecycleHook` can
+/// regardless). The split exists so PR 4's `PersonalDriveLifecycleHook` can
 /// trash on `AdminDelete` but hard-delete on `GdprPurge`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum DeletionMode {