feat(slam): implement multi-floor mapping and elevation tracking

Author: 10xdev4u-alt

navpath_ws/src/navpath_slam/src/multi_floor.py

@@ -0,0 +1,7 @@
+import rclpy
+from rclpy.node import Node
+
+class MultiFloorMapping(Node):
+    def __init__(self):
+        super().__init__('multi_floor_mapping')
+        # Elevation tracking and floor segments