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>

locales/ru-RU/opencadstudio.ftl

@@ -6598,3 +6598,39 @@ ucs-follow =
     .prompt = UCSFOLLOW: enter 0 (keep view) or 1 (follow UCS) <__ocs_fmt_0__>:
     .paper-space = UCSFOLLOW: activate a model viewport; paper space cannot follow the UCS.
     .invalid = UCSFOLLOW: only 0 or 1 is allowed.
+
+dgn-import =
+    .supported = Supported
+    .by-extension = By extension
+    .acis-solver = ACIS solver available
+    .export-only = Export only
+    .acis-reason = ACIS bodies are read only inside drawings; SAT files cannot be imported.
+    .step-reason = STEP files are only written (STEPOUT), not read.
+    .no-importer = OpenCAD Studio has no importer for this format.
+    .recent = Recent:
+    .group-2d = 2D / Underlay
+    .group-3d = 3D Model
+    .search = Search formats...
+    .only-supported = Only what OCS can open
+    .models = __ocs_fmt_0__ model(s)
+    .change = Change file...
+    .name-conflict = On name conflict
+    .prefix = Add prefix to dependent definitions
+    .ignore-duplicates = Ignore duplicate names
+    .master-unit = Master unit
+    .sub-unit = Sub unit
+    .explode = Explode text nodes to text elements
+    .references = External DGN references
+    .bind = Bind as block / xref
+    .attach = Attach as DGN underlay
+    .references-note = Reference attachments of DGN files are not read; they are left out.
+    .mapping = Property mapping
+    .mapping-standard = Standard mapping setup.
+    .mapping-note = The preview shows the selected setup's effect on this file.
+    .import-file = Import File
+    .dgn-import = DGN Import
+    .import-dgn-file = Import DGN File
+    .help-dgn = Imports a DGN model as drawing objects: levels as layers, cells as blocks.
+    .help-import = Imports a file of the chosen format with the format's importer.
+    .blank = Filename cannot be blank
+    .invalid-dgn = Invalid or unsupported DGN file.