feat(tablestyle): per-cell editing for Data/Header/Title rows

Each row's RowCellStyle is now editable in the Table Style manager:
text style name, text height, text & fill color (ACI), background-fill
toggle, and alignment (cycle through the 9 anchor positions). Margin and
per-cell buffers load on open/select via a shared load_tablestyle_bufs;
edits write through objects.values_mut() and bump geometry so tables
using the style re-render.

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

src/app/view.rs

@@ -119,6 +119,10 @@ impl OpenCADStudio {
                 selected_style,
                 &self.ts_hmargin,
                 &self.ts_vmargin,
+                &self.ts_cell_textstyle,
+                &self.ts_cell_height,
+                &self.ts_cell_textcolor,
+                &self.ts_cell_fillcolor,
             );
         }
         if Some(window_id) == self.mlstyle_window {