fix(sheetset): SVG icons and the shared context menu for palette rows

- The glyph-text icons (refresh, swap, remove, submenu and step arrows)
  are SVG icons from ui::icons (new REFRESH and SWAP) or plain labels.
- The custom RowMenu widget is removed: Sheet Views / Model Views rows use
  iced_aw::ContextMenu like the Sheet List rows, with a submenu expanding
  in place while hovered.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/ui/window/mod.rs

@@ -27,7 +27,6 @@ pub mod alias_editor;
 pub mod find_replace;
 pub mod named_parameters;
 pub mod pc_manager;
-pub mod row_menu;
 pub mod sheet_set;
 pub mod pdf_dialogs;
 pub mod xref_attach;