One canonical submitted geometry

Removes the competing Base64 geometry payload from the Planner form and server
Uses geometry_json as the single authoritative submitted mission geometry
Applies identical coordinate, minimum-edge, minimum-area, and intersection checks in browser and PHP
Reports the actual polygon rejection cause instead of one generic message
Preserves server-side route generation and transactional read-back verification
Verifies valid four-corner 2D and 3D areas through save, reload, edit, and resave
Universal install/update package supports Betas 0.15 through 0.33

Changelog