IMAGEADJUST: Image Adjust dialog for raster images

IMAGEADJUST (alias IAD) takes the selected raster images or asks
"Select image(s):", then opens a dialog with a before/after preview of
the first image and brightness, contrast and fade rows (bar plus
stepper, whole numbers 0-100). Apply writes the values to every chosen
image as one undo step; restore defaults sets 50/50/0. Adds the
image_adjust automation action and the image-adjust locale group.

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

src/app/view/modal.rs

@@ -40,6 +40,7 @@ impl OpenCADStudio {
                 crate::tr!("view-background", "title"),
                 self.view_background.as_ref().map_or("", |s| s.view.as_str())
             ),
+            Some(K::ImageAdjust) => crate::tr!("image-adjust", "title"),
             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(),
@@ -528,6 +529,12 @@ impl OpenCADStudio {
                     crate::ui::window::pdf_dialogs::view_background(state, flow)
                 })
             }
+            super::super::ModalKind::ImageAdjust => {
+                let state = self.image_adjust.as_ref()?;
+                sized_flow(ex, 520, 560, |flow| {
+                    crate::ui::window::pdf_dialogs::image_adjust(state, flow)
+                })
+            }
             super::super::ModalKind::UnderlayLayers => {
                 let state = self.underlay_layers.as_ref()?;
                 sized_flow(ex, 460, 520, |flow| {