fix(admin): polish categories

Add accessible names to select-all, per-row select, and per-row
visibility-toggle checkboxes in the table view — none had them,
including the visibility toggle whose <label> wrapped only the input
with no text content (empty accessible name). Tree/grid views already
had aria-label on their row checkboxes; table view was the gap.

New adminCategories.selectAllRows/selectRow/toggleVisibility keys
added across en/ru/hy.

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

src/app/i18n/en.ts

@@ -1448,6 +1448,9 @@ export const en: Translations = {
     replaceImage: 'Replace image',
     search: 'Search categories…',
     showDeleted: 'Show deleted',
+    selectAllRows: 'Select all categories',
+    selectRow: 'Select category',
+    toggleVisibility: 'Toggle visibility',
     create: 'Create category',
     edit: 'Edit category',
     title: 'Title',