Phase 2: do_attack now searches the mobs registry after players dict
when resolving a target name. Players always take priority over mobs
with the same name. World instance injected into combat/commands module
for wrapping-aware mob proximity checks.
Phase 1 of fightable mobs: MobTemplate dataclass loaded from TOML,
global mobs list, spawn_mob/despawn_mob/get_nearby_mob with
wrapping-aware distance. Mob entity gets moves and next_action_at fields.