Port Face Map planner to native Avalonia

[Rouniy]

Summary

• add the native Auto WP Face Map workflow with a draggable Mapsui preview and bench cross-section
• port official facade geometry, camera coverage, gimbal/yaw/trigger commands, safe split flights, RTL/Land, camera profiles and .facemap compatibility
• bound pathological geometry and XML input, fix upstream parallel-line and trigger edge cases, and document the remaining three parity gaps

Validation

• Release Face Map tests: 15 passed
• full Release suite: 1076 passed, 0 failed
• dotnet format verify-no-changes passed for changed C# files
• git diff --check passed
• no vulnerable direct or transitive NuGet packages reported