feat: donate links on login screen + unified README support block

- public/index.html: gate-donate nav with Boosty/Ozon/Telegram on login
- public/styles.css: .gate-donate styles
- landing: proj-support-strip
- README: blockquote + "Поддержка проекта" section
- .github/FUNDING.yml: added
- version bumped to 1.2.28

Co-authored-by: Cursor <cursoragent@cursor.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "amnezia-admin",
-  "version": "1.2.0",
+  "version": "1.2.28",
   "private": true,
   "description": "amnezia_web-PRO — веб-панель AmneziaWG: несколько инстансов, WARP, каскад/Endpoint, экспорт .conf (Docker)",
   "license": "MIT",