PDF dialogs: own look with cards, segmented choices and chips

Attach PDF Underlay, Underlay Layers, PDF Import Settings and Import PDF
are laid out with rounded cards and accent titles, segmented controls for
path type, import layers and rotation, toggle chips for the on-screen
choices and import options, a page preview with previous/next for Import
PDF, always-visible file details, and a footer with help on the left and
the named action (Attach, Apply, Save, Import) on the right.

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

locales/ru-RU/opencadstudio.ftl

@@ -3520,6 +3520,13 @@ insert =
     .pdfui-specify-insertion-point-on-screen = Specify insertion point on-screen
     .pdfui-page-size-size = Page size: __ocs_fmt_0__
     .pdfui-total-count = Total: __ocs_fmt_0__
+    .pdfui-pages = Pages
+    .pdfui-placement = Placement
+    .pdfui-on-screen = On screen
+    .pdfui-file-details = File details
+    .pdfui-page-count = __ocs_fmt_0__ pages
+    .pdfui-selected-pages = Selected pages: __ocs_fmt_0__
+    .pdfui-layer-summary = __ocs_fmt_0__ layers, __ocs_fmt_1__ hidden
     .pdfui-page = Page:
     .pdfui-page-to-import = Page to import
     .pdfui-infer-linetypes-from-collinear-dashes = Infer linetypes from collinear dashes