(core) Add cut, copy, and paste to context menu

Summary:
On supported browsers, the new context menu commands work exactly as they do
via keyboard shortcuts. On unsupported browsers, an unavailable command
modal is shown with a suggestion to use keyboard shortcuts instead.

Test Plan: Browser tests.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D3867

app/client/ui/FieldContextMenu.ts

@@ -0,0 +1,27 @@
+import {allCommands} from 'app/client/components/commands';
+import {makeT} from 'app/client/lib/localization';
+import {IRowContextMenu} from 'app/client/ui/RowContextMenu';
+import {menuDivider, menuItemCmd} from 'app/client/ui2018/menus';
+import {dom} from 'grainjs';
+
+const t = makeT('FieldContextMenu');
+
+export interface IFieldContextMenu {
+  disableModify: boolean;
+  isReadonly: boolean;
+}
+
+export function FieldContextMenu(_rowOptions: IRowContextMenu, fieldOptions: IFieldContextMenu) {
+  const {disableModify, isReadonly} = fieldOptions;
+  const disableForReadonlyColumn = dom.cls('disabled', disableModify || isReadonly);
+  return [
+    menuItemCmd(allCommands.contextMenuCut, t('Cut'), disableForReadonlyColumn),
+    menuItemCmd(allCommands.contextMenuCopy, t('Copy')),
+    menuItemCmd(allCommands.contextMenuPaste, t('Paste'), disableForReadonlyColumn),
+    menuDivider(),
+    menuItemCmd(allCommands.clearCardFields, t('Clear field'), disableForReadonlyColumn),
+    menuItemCmd(allCommands.hideCardFields, t('Hide field')),
+    menuDivider(),
+    menuItemCmd(allCommands.copyLink, t('Copy anchor link')),
+  ];
+}