feat(plot): Windows printer media and printable areas

The plot dialog asks CUPS printers for their sheets and margins; on Windows
the query was a stub, so every printer showed the paper catalogue with
unverified margins. The driver is now asked the way the plot dialog expects:

- windows_media (compiled and tested everywhere): the three parallel
  DeviceCapabilities tables (ids, sizes in tenths of a millimetre, 64-WCHAR
  names) become one PrinterMedia per distinct size — a rotated or
  borderless twin folds onto its sheet, catalogue sheets keep their name,
  unknown sizes carry the driver's — with the device's margins on every
  entry and the driver's default sheet found by id or by user size.
- print_to_printer (Windows): DeviceCapabilitiesW for the tables, the
  default DEVMODE for the default sheet, one portrait printer DC for the
  unprintable margins (physical offsets and extents, per device — a
  documented approximation). The DEVMODE fetch is shared with the print
  path (with_printer_devmode).
- A direct print now asks the driver for the plot's own sheet (by id, or
  as a user-defined size), so an A3 plot prints on A3 rather than shrunk
  into the driver's default; a driver that refuses the sheet is asked for
  the orientation alone.
- The capability cache remembers printers that could not be asked, so a
  slow failing query runs once per session, not on every dialog open.
- PRINTERS <name> reports a printer's sheets, margins and default sheet.

Tests: names (NUL trim, full slot, lossy), media folding and dropping,
default by id / user size / none, DC margins, paper id lookup.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

locales/ru-RU/opencadstudio.ftl

@@ -5100,6 +5100,10 @@ plot =
     .system-default-printer = Системный принтер по умолчанию
     .what-to-plot = Что спланировать
     .x-mm = X (мм)
+    .printer-the-printer-reports-no-sheets-the-paper-catalogue-is-used = __ocs_fmt_0__: принтер не сообщает форматов; используется каталог бумаги.
+    .printer-count-sheet-s-reported = __ocs_fmt_0__: сообщено форматов: __ocs_fmt_1__
+    .default-sheet-sheet = Формат по умолчанию: __ocs_fmt_0__
+    .default-sheet-not-reported = Формат по умолчанию: не сообщён
     .default-printer-name = Принтер по умолчанию: __ocs_fmt_0__
     .default-printer-none-reported-by-the-system = Принтер по умолчанию: система не сообщает ни об одном
     .printers-none-listed-by-the-system = Принтеры: система не перечисляет ни одного