Point cloud extraction: structured scans only

Plane and cylinder picks ask again and section extraction gives nothing
on a scan without segments, as the reference does with unstructured
scans (scan segmentation is not decoded yet). The section dialog's time
estimate reads in minutes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

locales/ru-RU/opencadstudio.ftl

@@ -4008,7 +4008,7 @@ insert =
     .pcs-max-points = Maximum points to process
     .pcs-faster = Faster
     .pcs-accurate = More accurate
-    .pcs-time = Estimated time: __ocs_fmt_0__ min
+    .pcs-time = Estimated time: __ocs_fmt_0__ minutes
     .pcs-output = Output geometry
     .pcs-polylines = 2D Polylines
     .pcs-width = Polyline width