feat: FAQ pages — Q&A builder in admin, accordion view for users

Admin editor:
- page_type selector: "Страница" / "FAQ" radio buttons
- When FAQ: FaqBuilder component replaces TipTap editor
  - Question input + answer textarea per Q&A item
  - Add/remove items, up/down reorder buttons
  - Per-locale Q&A (stored as JSON array in content JSONB)
- "Создать FAQ" button in list alongside "Создать страницу"
- Filter tabs: Все / Страницы / FAQ
- Page type badge on each row (accent for pages, amber for FAQ)

Public view (InfoPageView):
- Auto-detects page_type='faq' and renders FaqView component
- Accordion with smooth height animation (300ms ease-in-out)
- Search filter appears when >3 questions
- DOMPurify sanitization on FAQ answers
- Single-item expand (click to open/close)

i18n: full FAQ keys for all 4 locales (questions, answers,
search, counts, empty states, builder labels)

src/locales/en.json

@@ -3804,6 +3804,7 @@
       "title": "Information Pages",
       "subtitle": "Manage static information pages",
       "create": "Create Page",
+      "createFaq": "Create FAQ",
       "edit": "Edit",
       "save": "Save",
       "saving": "Saving...",
@@ -3815,6 +3816,7 @@
       "notFound": "Page not found",
       "active": "Active",
       "inactive": "Inactive",
+      "typePage": "Page",
       "localeLabel": "Content Language",
       "fields": {
         "slug": "URL Slug",
@@ -3822,7 +3824,34 @@
         "content": "Content",
         "isActive": "Active",
         "sortOrder": "Sort Order",
-        "icon": "Icon (emoji)"
+        "icon": "Icon (emoji)",
+        "pageType": "Page Type"
+      },
+      "filter": {
+        "all": "All",
+        "page": "Pages",
+        "faq": "FAQ"
+      },
+      "pageTypes": {
+        "page": "Page",
+        "faq": "FAQ"
+      },
+      "faq": {
+        "questions": "Questions & Answers",
+        "questionsCount": "questions",
+        "noQuestions": "No questions yet. Click the button below to add one.",
+        "questionNumber": "Question #{{n}}",
+        "question": "Question",
+        "answer": "Answer",
+        "questionPlaceholder": "Enter question...",
+        "answerPlaceholder": "Enter answer (HTML supported)...",
+        "htmlHint": "HTML markup is supported",
+        "addQuestion": "Add Question",
+        "removeQuestion": "Remove question",
+        "moveUp": "Move up",
+        "moveDown": "Move down",
+        "searchPlaceholder": "Search questions...",
+        "noResults": "No results found"
       },
       "locales": {
         "ru": "Russian",