=== 2.4 TWO RESTORES AT ONCE (direct POST, back to back) ===
--- the log must show ONE start and ONE refusal ---
off-box restore refused for bookstack (mode=unit): another backup/restore op is already running
off-box restore docmost completed (full=false, async)

scratch dirs created (exactly one app expected):
bookstack calibre-web docmost kimai paperless-ngx 
