Add current-draft diagnostic underlines and passive hover

Preserve raw include diagnostic provenance and derive bands from the existing shaped editor. Retain deferred tooltip paragraphs through rendering. Include source, regression, failure and native-trial evidence; corrected native acceptance remains pending.

crates/oa-desktop/src/views/text_workspace.rs

@@ -15,6 +15,7 @@ pub(crate) const STRIP_HEIGHT: f32 = 42.;
 pub(crate) const FIND_HEIGHT: f32 = 36.;
 pub(crate) const DRAWER_HEIGHT: f32 = 180.;
 pub(crate) const STATUS_HEIGHT: f32 = 22.;
+const EDITOR_PADDING: f32 = 16.;
 
 /// The caller supplies one persistent diagnostic Guard, including when hidden
 /// (None publication and empty child). References is empty while hidden; its
@@ -62,12 +63,19 @@ pub(super) fn view<'a>(
         })
         .font(Font::MONOSPACE)
         .size(14)
-        .padding(16)
+        .padding(EDITOR_PADDING)
         .height(Fill)
         .highlight_with::<crate::highlight::ArcadiaHighlighter>(
             app.source_snapshot.clone(),
             crate::highlight::format,
         );
+    let editor = crate::source_annotations::Decorations::new(
+        editor,
+        &app.source_editor,
+        app.source_annotation_snapshot(),
+        iced::Padding::new(EDITOR_PADDING),
+        app.source_navigation_available(),
+    );
     let editor = widget::sensor(editor)
         .key((
             app.source_workspace.active.clone(),