feat(scale): drive scales from the drawing's scale list

Read the model-space annotation scale from the standard CANNOSCALE /
CANNOSCALEVALUE header variables instead of a user-variable hack, and
populate both the status-bar scale picker and the viewport Scale
property purely from the drawing's ACAD_SCALELIST — no built-in
fallback set. Xref-derived scales (`_XREF` suffix, `name|` prefix)
are filtered out so only the host drawing's own scales appear.

Bumps the patched acadrust to the commit that adds CANNOSCALE/
CANNOSCALEVALUE read/write.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/view.rs

@@ -1163,6 +1163,7 @@ impl OpenCADStudio {
                 is_model,
                 tab.scene.annotation_scale,
                 tab.scene.first_viewport_scale(),
+                tab.scene.scale_list(),
             )
         } else {
             iced::widget::Space::new().width(0).height(0).into()