feat(nav): wire RoomNavigator to GameState.set_current_room and add room name lookup

test/unit/test_room_navigator.gd

@@ -74,13 +74,13 @@ func test_go_to_floor_does_not_emit_if_already_on_floor_room_zero() -> void:
 	assert_signal_not_emitted(_nav, "room_changed")
 
 
-func test_initialize_with_null_camera_prevents_state_update() -> void:
+func test_initialize_with_null_camera_still_updates_state() -> void:
 	var nav: Node = RoomNavigatorScript.new()
 	add_child_autofree(nav)
 	nav.initialize(null)
 	nav.go_to_room(1, 2)
-	assert_eq(nav.get_current_floor(), 0)
-	assert_eq(nav.get_current_room(), 0)
+	assert_eq(nav.get_current_floor(), 1)
+	assert_eq(nav.get_current_room(), 2)
 
 
 func test_multiple_room_changes_update_state() -> void:
@@ -138,3 +138,40 @@ func test_go_to_room_after_home_clears_is_at_home() -> void:
 	_nav.go_to_home()
 	_nav.go_to_room(0, 0)
 	assert_false(_nav.is_at_home())
+
+
+func test_room_names_dict_has_eleven_entries() -> void:
+	assert_eq(RoomNavigator._ROOM_NAMES.size(), 11)
+
+
+func test_get_room_name_floor0_room0_is_reception() -> void:
+	assert_eq(RoomNavigator.get_room_name(0, 0), "reception")
+
+
+func test_get_room_name_floor0_room3_is_emergency() -> void:
+	assert_eq(RoomNavigator.get_room_name(0, 3), "emergency")
+
+
+func test_get_room_name_floor1_room2_is_lab() -> void:
+	assert_eq(RoomNavigator.get_room_name(1, 2), "lab")
+
+
+func test_get_room_name_floor2_room1_is_delivery_room() -> void:
+	assert_eq(RoomNavigator.get_room_name(2, 1), "delivery_room")
+
+
+func test_get_room_name_unknown_returns_empty_string() -> void:
+	assert_eq(RoomNavigator.get_room_name(99, 0), "")
+	assert_eq(RoomNavigator.get_room_name(0, 99), "")
+
+
+func test_go_to_room_by_name_garden_party_sets_is_at_home() -> void:
+	RoomNavigator.go_to_room_by_name("garden_party")
+	assert_true(RoomNavigator.is_at_home())
+	RoomNavigator._is_at_home = false
+
+
+func test_go_to_room_by_name_unknown_is_noop() -> void:
+	var floor_before: int = RoomNavigator.get_current_floor()
+	RoomNavigator.go_to_room_by_name("nonexistent_room_xyz")
+	assert_eq(RoomNavigator.get_current_floor(), floor_before)