HomeSyncHub SMTP Recovery Email Setup

This build is wired for PHPMailer SMTP recovery emails.

Fast setup on Windows/XAMPP:
1. Extract HomeSyncHub into C:\xampp\htdocs\HomeSyncHub
2. Install Composer for Windows if it is not already installed.
3. Double-click setup_smtp_windows.bat from the HomeSyncHub folder.
4. Enter your SMTP details.
   Gmail example:
   - Host: smtp.gmail.com
   - Port: 587
   - Encryption: tls
   - Username: your Gmail address
   - Password: Google App Password, not normal Gmail password
5. Let the script send a test email.
6. Restart Apache in XAMPP.
7. Test the Recover page.

Recovery behavior:
- User enters registered email.
- HomeSyncHub creates a 6-digit recovery code.
- HomeSyncHub sends the code through PHPMailer SMTP.
- User enters the code in HomeSyncHub.
- User creates a new password.
- The recovery code expires after 10 minutes and becomes single-use after reset.

Files added:
- composer.json
- includes/mailer.php
- includes/smtp_config.php
- setup_smtp_windows.bat
- tools/configure_smtp.php
- tools/test_smtp.php

Security notes:
- Never use your normal Gmail password. Use an app password.
- Keep includes/smtp_config.php private.
- Do not upload smtp_config.php with real passwords to public GitHub.
