Add password reset functionality and SMTP mailer class

- Implemented reset-password.php for users to reset their passwords securely.
- Added validation for reset tokens and password strength checks.
- Created mailer.php to handle sending emails via SMTP, including password reset and invitation emails.
- Integrated responsive HTML email templates for better user experience.

auth/login.php

@@ -215,7 +215,10 @@ $pageTitle = "Fociz — Inloggen";
             </div>
 
             <div>
-                <label class="block text-xs font-semibold text-slate-700 dark:text-slate-300 mb-1">Wachtwoord</label>
+                <div class="flex items-center justify-between mb-1">
+                    <label class="block text-xs font-semibold text-slate-700 dark:text-slate-300">Wachtwoord</label>
+                    <a href="/auth/forgot-password.php" class="text-xs text-indigo-600 dark:text-indigo-400 hover:underline font-medium">Wachtwoord vergeten?</a>
+                </div>
                 <div class="relative">
                     <input type="password" name="password" required placeholder="••••••••" class="w-full bg-slate-50 dark:bg-[#0c0f17] border border-slate-300 dark:border-slate-800 rounded-xl px-4 py-2.5 text-slate-900 dark:text-white placeholder-slate-400 dark:placeholder-slate-500 focus:outline-none focus:ring-1 focus:ring-indigo-500 text-sm transition">
                 </div>