feat(ui): add press-to-capture shortcut editing to Keyboard Shortcuts dialog

Replace manual key entry with per-row capture cells: clicking + Add
inserts a draft row at the top with its key cell armed, and the next
key combination is recorded and normalized (Ctrl+Shift+S →
CTRL+SHIFT+S). While armed, a dedicated keyboard listener swallows all
input so recorded shortcuts do not execute in the drawing.

Draft rows are transient and confirmed only through an explicit accept
button, so the table never retains empty rows. Duplicate keys and
unrunnable commands are flagged in danger styling with a persistent
warning naming the conflicting command. Added reset-to-defaults with
confirmation, apply-and-exit, a shortcut count, and an unsaved-changes
guard on close.

src/ui/icons.rs

@@ -531,6 +531,17 @@ pub fn themed_success<'a, M: 'a>(bytes: &'static [u8], size: f32) -> Element<'a,
         .into()
 }
 
+/// Render an icon with the foreground chosen for a success-coloured surface.
+pub fn themed_success_text<'a, M: 'a>(bytes: &'static [u8], size: f32) -> Element<'a, M> {
+    svg(themed_handle(bytes))
+        .width(size)
+        .height(size)
+        .style(|theme: &Theme, _| svg::Style {
+            color: Some(theme.palette().success.base.text),
+        })
+        .into()
+}
+
 /// Render a warning-state chrome icon from the active Iced theme.
 pub fn themed_warning<'a, M: 'a>(bytes: &'static [u8], size: f32) -> Element<'a, M> {
     svg(themed_handle(bytes))