refactor: migrace vsech formularu na FormField komponentu + JWT upgrade

- FormField.jsx: pridana podpora style prop
- 23 stranek migrovano na FormField (166 vyskytu, -246 radku)
- firebase/php-jwt upgrade v6.11 -> v7.0.3 (security advisory fix)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

composer.json

@@ -4,7 +4,7 @@
     "type": "project",
     "require": {
         "php": ">=8.1",
-        "firebase/php-jwt": "^6.11",
+        "firebase/php-jwt": "^7.0",
         "robthree/twofactorauth": "^3.0",
         "chillerlan/php-qrcode": "^5.0"
     },