fix(ui): highlight the menu row under the pointer (#1242)

Menu rows now follow the pointer without taking focus: focusing the row on every pointer enter dropped the hover paint in the Windows webview, so menus looked frozen. Keyboard navigation continues from the hovered row, and an item's onActive fires once per enter. Focus no longer scrolls the page when a menu row takes it.

On Solarized Dark the selection and hover colours were the popup and panel colour, so menu, tree, list and tab selection was invisible there; on Solarized Light selection matched the panels. Both themes get distinct selection and hover colours, and the editor keeps Solarized's own selection colour.

Co-authored-by: tomgor <[email protected]>

src/workbench/MainMenu.tsx

@@ -229,6 +229,9 @@ function MainMenuBar({ merged, onExpandedChange }: MainMenuProps & { merged: boo
           onPointerEnter={() => {
             if (open !== null) setOpen(i);
           }}
+          onMouseEnter={() => {
+            if (open !== null) setOpen(i);
+          }}
           onClick={() => {
             if (open === i) close();
             else setOpen(i);