Gestaltung panel now shows pen controls (color, lineweight, linetype)
when nothing is selected. Settings persist in sticky and are stamped
onto every newly drawn object (curves, text, hatch, dims — not 3D
solids or DOSSIER element geometry) via the existing AddRhinoObject
listener. Active state shown with badge; resets by switching all back
to "Nach Ebene".
Also adds csharp/BUILD.md with full build + post-reinstall checklist.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>