import: IMPORT window and DGNIMPORT converting DGN models to drawing objects

The DGN V7/V8 readers expose each element (level, symbology, geometry,
complex chains, text nodes, shared cells). DGNIMPORT / -DGNIMPORT convert a
model with the Standard mapping into a new drawing; IMPORT opens the
Import File window and routes PDF and DGN files to their importers.

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

src/app/view/modal.rs

@@ -47,6 +47,8 @@ impl OpenCADStudio {
             Some(K::UnderlayLayers) => crate::t!("Underlay Layers").into_owned(),
             Some(K::PdfImportSettings) => crate::t!("PDF Import Settings").into_owned(),
             Some(K::PdfImportFile) => crate::t!("Import PDF").into_owned(),
+            Some(K::ImportFile) => crate::t!("Import File").into_owned(),
+            Some(K::DgnImport) => crate::t!("DGN Import").into_owned(),
             Some(K::XrefAttach) => crate::t!("Attach External Reference").into_owned(),
             Some(K::WriteBlock) => crate::t!("Write Block").into_owned(),
             Some(K::GeometricTolerance) => crate::t!("Geometric Tolerance").into_owned(),
@@ -581,6 +583,19 @@ impl OpenCADStudio {
                     crate::ui::window::pdf_dialogs::view_import_file(state, flow)
                 })
             }
+            super::super::ModalKind::ImportFile => {
+                let state = self.import_dialogs.file.as_ref()?;
+                let recent = &self.import_dialogs.recent;
+                sized_flow(ex, 960, 620, |flow| {
+                    crate::ui::window::import_dialogs::view_import_file(state, recent, flow)
+                })
+            }
+            super::super::ModalKind::DgnImport => {
+                let state = self.import_dialogs.dgn.as_ref()?;
+                sized_flow(ex, 900, 680, |flow| {
+                    crate::ui::window::import_dialogs::view_dgn_import(state, flow)
+                })
+            }
             super::super::ModalKind::XrefAttach => {
                 let state = self.xref_attach.as_ref()?;
                 let height = if state.details { 520 } else { 450 };