PCEXTRACTSECTION: Extract Section Lines dialog

Picking the cloud opens the Extract Section Lines from Point Cloud
dialog with the reference's settings and defaults: entire cross section
or perimeter only, maximum points to process (slider and field, with
the estimated time), output layer (Use Current or a layer), colour,
lines or 2D polylines with their width, minimum line length and connect
lines tolerance (each measurable by two points on screen), collinear
angle tolerance (0-10) and Preview result. Create extracts; with the
preview it asks [Accept/Settings/Undo] and Settings reopens the dialog.
The settings are kept for the session. Automation action pc_section.

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

src/app/update/mod.rs

@@ -8485,6 +8485,11 @@ impl OpenCADStudio {
             }
 
             Message::CloseModal => {
+                // Cancelling the section settings drops the waiting extraction.
+                if self.active_modal == Some(super::ModalKind::PcSection) {
+                    crate::modules::insert::pc_extract::drop_job();
+                    self.pc_section = None;
+                }
                 if self.active_modal == Some(super::ModalKind::RecoveryPrompt) {
                     return self.update(Message::RecoveryDecline);
                 }