PHP Security Priority: P0 (CRITICAL) Structure Implementation Guidelines - Prepared Statements : Use PDO with Parameterized Queries: . NEVER concatenate user input into SQL strings. - Password Hashing : ALWAYS use with (PHP 7.4+) or . - Auth Verification : Use . Use to upgrade legacy hashes. Implement Rate Limiting and MFA where appropriate. - XSS Escaping : Use or on all user output. Prefer Twig or Blade for auto-escaping. - CSRF Protection : Mandate for all state-changing requests ( , , , ). - Input Validation : Use or . Always Whitelist allowed values. - File Security : RESTRICT file uploa…