feat(dimstyle): add Annotative toggle to the Dimension Style editor

Adds the annotative property (DsField::Annotative) to the dim-style edit
buffers, load/apply, and a checkbox on the Fit/Scale tab — consistent with
the Text Style editor's annotative toggle.

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

src/app/view.rs

@@ -215,6 +215,7 @@ impl OpenCADStudio {
                     dimtm: &self.ds_dimtm,
                     dimtdec: &self.ds_dimtdec,
                     dimtfac: &self.ds_dimtfac,
+                    annotative: self.ds_annotative,
                 },
             );
         }