Background dialog: adjust an image's offset and scale; visual style names

- The Image tab gains an Adjust card: X/Y offset in pixels (-2000..2000)
  and X/Y scale (-10..10, tenth steps, a negative scale mirrors, zero keeps
  the image's scale) with spinners and Reset, inactive while the image is
  stretched; Keep aspect ratio is a switch and makes both scales follow.
- The preview shows the image at its offset and scale, tiled when tiled,
  and a stretched image kept to its aspect ratio covers the view.
- Automation: step=<field>,+1|-1 and reset; offset/scale take any numbers.
- Shaded with edges, Shades of Gray and Sketchy have catalog entries in
  every language.

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

locales/es-ES/opencadstudio.ftl

@@ -867,9 +867,12 @@ common =
     .sent-to-printer-printer = Enviado a la impresora: __ocs_fmt_0__
     .set-current = Establecer actual
     .shade-plot = Trazado sombreado
+    .shaded-with-edges = Sombreado con aristas
+    .shades-of-gray = Tonos de gris
     .shadow-flags = Indicadores de sombra
     .single = Único
     .size = Tamaño
+    .sketchy = Bosquejo
     .snap-override-label-next-pick-only = Modificación de referencia: __ocs_fmt_0__ (solo la siguiente designación).
     .solid-created = Se creó el sólido.
     .source-object-not-found = No se encontró el objeto de origen.
@@ -6333,8 +6336,11 @@ view-background =
     .stretch = Stretch
     .tile = Tile
     .scale = Scale
-    .fit = Fit to screen
     .aspect = Keep aspect ratio
+    .adjust = Adjust
+    .reset = Reset
+    .offset = Offset
+    .pixels = px
     .no-image = No image selected
     .canvas = Drawing area color
     .info = Info