WebODM Boundary in Mission Planner

Adds a WebODM Boundary workflow to 2D and 3D Mission Planner missions without changing or extending the separate WebODM Offline Export Plugin.
Lets the user disable the Boundary, reuse the flown mapping area, or draw and edit a separate processing Boundary while keeping the flight area unchanged.
Stores the Boundary inside the existing mission geometry JSON and validates custom Boundary polygons with the same coordinate, edge, area, and self-intersection rules as mission polygons.
Shows the active Boundary as a dedicated blue dashed map overlay with a clear status, corner count, and approximate area before the coordinates are used elsewhere.
Adds a Boundary coordinates dialog containing the complete closed coordinate ring and WebODM-compatible WGS84 GeoJSON FeatureCollection.
Adds a one-click Copy Boundary action that copies the complete GeoJSON to the clipboard without requiring manual text selection and confirms a successful copy.
Keeps the current 200-waypoint RC2/DJI Fly test limit unchanged and introduces no WebODM server/API task automation.