Fix #967: Removed repeated global path republishes + Button to change global waypoints during run

[MilcToast]

Description

• Resolves PATH: Update node_mock_global_path.py #967

Changes Made

• Removed the GPS subscription and global_path_callback from node_mock_global_path.py, the node no longer republishes the global path on every GPS message
• Added a one-time publish at startup via publish_global_path, called before rclpy.spin
• Added a CSV file (global_paths/mock_global_path.csv) as a path source, with previous working path kept as a fallback if the CSV fails to load
• Added a reload_token ROS 2 parameter and _on_set_parameters callback to support runtime reloading, setting reload_token to any new value re-reads the CSV and republishes the global path
• Added a "Mock Global Path" control panel to the visualizer with a "Reload CSV" button that triggers the reload via ros2 param set /mock_global_path reload_token <n_clicks>

Verification

• Confirmed that node_mock_global_path no longer continuously republishes on GPS messages (only logs once)
• Confirmed that the global path is published once at startup and received by subscribers
• Confirmed that editing mock_global_path.csv and clicking "Reload CSV" in the visualizer triggers a republish with the updated waypoints
• Confirmed that the visualizer displays a success/error message after clicking "Reload CSV"

[raghumanimehta]

my bad, the requirements were not clear ig... we want to use the global path from the test plans.

I think a good design could be editting the mock_global_path.csv with new values then clicking the button on gui to change the global path to the one from csv i.e. stop using the one from test plan.

any questions?