feat: add NPC schedules with sleep, meal, and work periods

Add ACTION_SLEEP with home-position targeting and energy restoration. Embed schedule periods (SLEEP/MEAL/WORK/DISCRETIONARY) in ActionSelectionSystem with TimeOfDay from SimulationClock. NPCs sleep at night when energy is low, eat during meal periods when hungry, and work/discretionary the rest of the cycle. Home position stored per NPC and serialized through NPCStateRecord with backward-compatible fallback. Cycle duration persisted through save/restore. Includes headless test for sleep period, work period, meal hunger, energy restoration, serialization round-trip, and home targeting without world adapter.

tests/simulation_definitions_test.gd

@@ -34,7 +34,7 @@ func _test_registry_integrity() -> void:
 			SimulationDefinitions.get_action(definition.action_id) == definition,
 			"Action lookup should return '%s'" % definition.action_id
 		)
-	_check(action_ids.size() == 9, "Registry should contain all nine executable prototype actions")
+	_check(action_ids.size() == 10, "Registry should contain all ten executable prototype actions")
 
 	var profession_ids := SimulationDefinitions.get_profession_ids()
 	_check(profession_ids.size() == 5, "Registry should contain all five prototype professions")