Add two-factor authentication fields to pp_users table and update .htaccess for security

- Added columns for two-factor authentication (2FA) in the pp_users table:
  - twofa_enabled (TINYINT)
  - twofa_email (VARCHAR)
  - twofa_code_hash (VARCHAR)
  - twofa_expires_at (DATETIME)
  - twofa_sent_at (DATETIME)
  - twofa_failed_attempts (INT)
- Updated the twofa_enabled and twofa_email for user with id 0.
- Enhanced .htaccess to disable directory listing, block execution of sensitive files, and prevent serving hidden files.

plugins/.htaccess

@@ -0,0 +1,20 @@
+# Wyłącz listowanie
+Options -Indexes
+
+# Domyślnie blokujemy wszystko…
+Require all denied
+
+# …a dopiero potem pozwalamy na pliki statyczne
+<FilesMatch "\.(css|js|map|mjs|png|jpe?g|gif|svgz?|webp|ico|woff2?|woff|ttf|eot)$">
+    Require all granted
+</FilesMatch>
+
+# Twardo blokuj cokolwiek, co mogłoby się wykonać
+<FilesMatch "\.(php|phtml|php[0-9]?|phar|pht|cgi|pl|py|sh)$">
+    Require all denied
+</FilesMatch>
+
+# Nie serwuj plików ukrytych (.env itp.)
+<FilesMatch "^\.(.*)$">
+    Require all denied
+</FilesMatch>