feat: information pages — admin editor with TipTap, public viewer

Admin panel:
- New section "Информационные страницы" in admin nav
- Admin list: slug, title, active toggle, edit/delete, sort order
- Admin editor: full TipTap (bold, italic, headings, lists, links,
  image/video upload, alignment, highlight, code blocks)
  with locale tabs (RU/EN/ZH/FA) for title and content
- Create/edit via URL params, slug auto-generation

Public:
- /info/:slug route with DOMPurify sanitized content
- Locale fallback, Telegram safe area, loading skeleton, 404

i18n: all 4 locales

src/locales/en.json

@@ -1126,7 +1126,8 @@
       "landings": "Landings",
       "referralNetwork": "Referral Network",
       "news": "News",
-      "bulkActions": "Bulk Actions"
+      "bulkActions": "Bulk Actions",
+      "infoPages": "Info Pages"
     },
     "panel": {
       "title": "Admin Panel",
@@ -3798,6 +3799,37 @@
         "prev": "Previous",
         "next": "Next"
       }
+    },
+    "infoPages": {
+      "title": "Information Pages",
+      "subtitle": "Manage static information pages",
+      "create": "Create Page",
+      "edit": "Edit",
+      "save": "Save",
+      "saving": "Saving...",
+      "saved": "Page saved",
+      "delete": "Delete",
+      "confirmDelete": "Delete this page?",
+      "saveError": "Failed to save page. Please try again.",
+      "noPages": "No information pages yet",
+      "notFound": "Page not found",
+      "active": "Active",
+      "inactive": "Inactive",
+      "localeLabel": "Content Language",
+      "fields": {
+        "slug": "URL Slug",
+        "title": "Title",
+        "content": "Content",
+        "isActive": "Active",
+        "sortOrder": "Sort Order",
+        "icon": "Icon (emoji)"
+      },
+      "locales": {
+        "ru": "Russian",
+        "en": "English",
+        "zh": "Chinese",
+        "fa": "Persian"
+      }
     }
   },
   "adminUpdates": {