fix(exam,result,question): kebab-icon action menus, status change as a picker

Two follow-ups on the dropdown-actions pass:
- All four action menus (exams, results, questions, candidates panel) now
  trigger off a plain three-dot icon button instead of a text 'Actions'
  button with a chevron.
- Exam status change no longer lists all six statuses flat in the dropdown
  (bad UX, looked like six always-visible options). 'Status' is now one
  menu item that opens a small picker modal (current status + a Select +
  Update) rather than the full edit form.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/backoffice/src/app/features/result/pages/ResultPage/actions.tsx

@@ -1,5 +1,5 @@
-import { Button, Menu } from '@mantine/core';
-import { IconChevronDown, IconEye, IconSend, IconTrash } from '@tabler/icons-react';
+import { ActionIcon, Menu } from '@mantine/core';
+import { IconDotsVertical, IconEye, IconSend, IconTrash } from '@tabler/icons-react';
 import type { TFunction } from 'i18next';
 import type { AdvancedColumn } from '@ema-platform/ui';
 import { LICENSE_PERMISSIONS, RequirePermission } from '@ema-platform/auth';
@@ -24,9 +24,9 @@ export function resultActionsColumn(
       return (
         <Menu shadow="md" width={180} position="bottom-end">
           <Menu.Target>
-            <Button size="compact-xs" variant="light" rightSection={<IconChevronDown size={12} />}>
-              {t('result.columns.actions', 'Actions')}
-            </Button>
+            <ActionIcon variant="subtle" color="gray" size="sm">
+              <IconDotsVertical size={16} />
+            </ActionIcon>
           </Menu.Target>
           <Menu.Dropdown>
             <Menu.Item leftSection={<IconEye size={14} />} onClick={() => handlers.onViewDetail(r)}>