feat(admin): visual badge manager with storefront-accurate previews

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

P0 user feedback: badges were a comma-separated text input with no preview.

- Replaced with a chip editor: current badges render as removable pills in the exact colors customers see on the storefront (colors sourced from getBadgeClass/item.utils.ts so admin preview and product card never drift)
- The standard set (new/sale/exclusive/hot/limited/bestseller/featured) is offered as one-click add chips; custom badges added via text field, unlimited, shown in the storefront's custom-badge grey
- Deliberately NOT per-badge arbitrary colors: badge colors are part of the storefront design contract (string[] + fixed palette); introducing per-badge color storage would change the product data shape consumed by the future backend
- New adminProducts keys (badgesHint, addBadge, removeBadge, customBadgePlaceholder) in en/ru/hy; verified in browser

src/app/i18n/en.ts

@@ -1546,6 +1546,10 @@ export const en: Translations = {
     seoGenerate: 'Fill from product details',
     seoGenerateHint: 'Fills empty fields from the product name and short description. Your existing text is kept.',
     translationsHint: 'The main fields above are shown in your default store language. Add translations here for other languages - if a translation is empty, customers see the default text instead.',
+    badgesHint: 'Badges are the small colored labels customers see on the product photo. Pick from the standard set or add your own.',
+    addBadge: 'Add',
+    removeBadge: 'Remove badge',
+    customBadgePlaceholder: 'Your own badge text…',
     seoExplain: 'This is what shows up in search results — a clear title and description help customers find this product.',
     searchTitle: 'Search title',
     searchTitleHint: 'The headline shown in search results. Keep it short and descriptive.',