fix(design): a right-click on selected words opens the browser's own menu (E28 S3e4b)

The row menu took every right-click, so selected text could only be copied
with Ctrl+C. On the selection (its laid-out line boxes) the event is left to
the browser; beside it the object's menu opens as before.

frontend/src/components/ui/useContextMenu.ts

@@ -7,6 +7,7 @@ import {
 } from "react";
 
 import { matchesShortcut, useKeyScope } from "../../lib/keymap";
+import { pointOnSelection } from "../../lib/textSelection";
 import { useAnchoredPopover } from "./anchoredPopoverHooks";
 
 // E10 S2 — the right-click context menu's INPUT half: the gestures that open it and the row they
@@ -19,7 +20,8 @@ import { useAnchoredPopover } from "./anchoredPopoverHooks";
 // cannot grow a right-click menu that looks or behaves unlike its own ⋯ menu.
 //
 // Three ways in, because a menu that only opens one way does not exist on the device that lacks it:
-//   - right-click anywhere on the row (the desktop browser, and the reason this sprint exists),
+//   - right-click anywhere on the row (the desktop browser, and the reason this sprint exists) —
+//     except on selected words, where the browser's own menu opens so they can be copied,
 //   - long-press (touch/pen only) — the tablet has no right button,
 //   - Shift+F10 / the Menu key, which is free once the row is in the tab order.
 // The left button is untouched: it keeps the row's own default action (select / play).
@@ -158,9 +160,11 @@ export function useContextMenu<T>({
       // menu instead of Safari's own link/image callout on top of it.
       "data-context-menu-target": "",
       onContextMenu: (e: React.MouseEvent<HTMLElement>) => {
-        e.preventDefault();
         // A row inside another context-menu target (a table inside a panel) claims the event.
         e.stopPropagation();
+        // On selected words the browser's own menu opens (Copy, Search): DESIGN "Text stays selectable".
+        if (pointOnSelection(e.target, e.clientX, e.clientY)) return;
+        e.preventDefault();
         openAt(e.clientX, e.clientY, payload, e.currentTarget);
       },
       onPointerDown: (e: ReactPointerEvent<HTMLElement>) => {