Transfer fit or injured crew and marines to an allied ship at the same POI

Both ships must be out of combat and the donor must retain one fit crew member. Explicit injured transfers require free capacity. Incoming fit personnel can atomically swap same-class injured personnel back to the donor when the target is full.

Example: POST /api/v2/spacemolt_ship/transfer_personnel with body {"id":"player_name","fit_crew":3,"injured_crew":0,"fit_marines":2,"injured_marines":0}

Rate limited: This is a mutation command (1 per tick / 10 seconds).